Skocz do pozycji: 1.

Tytuł:

Heat transfer analysis for the hydraulic circuit of an expresso-coffee machine

Autorzy:

Fioretti, L.
Conti, M.

Powiązania:

https://bibliotekanauki.pl/articles/1964076.pdf

Data publikacji:

2001

Wydawca:

Politechnika Gdańska

Tematy:

heat transfer

Opis:

An Espresso-Coffee Machine supplies water which temperature must be confined within a narrow range in different operating conditions; this requires an accurate design at the component as well as the system level. In the present paper we develop a mathematical model to analyse the performances of the heating circuit of such a machine; our aim is to capture the main operating characteristics of the system with the maximum of simplicity. The governing equations of the model have been solved with the finite difference technique, and the first results have been compared with some experimental data.

Źródło:

TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2001, 5, 1; 99-107
1428-6394

Pojawia się w:

TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 2.

Tytuł:

Calculation of heat transfer in fluid around gas-vapour bubbles

Autorzy:

Pavlenko, A.
Koshlak, H.

Powiązania:

https://bibliotekanauki.pl/articles/402555.pdf

Data publikacji:

2017

Wydawca:

Politechnika Świętokrzyska w Kielcach. Wydawnictwo PŚw

Tematy:

heat transfer coefficient
dispersed phase
mathematical model
heat transfer

Opis:

In this paper the mathematical model for calculating heat transfer in the fluid that surrounds the oscillating gas – steam bubble. The mathematical model takes into account the changing thermal and physical characteristics the liquid, changing the size of bubbles, heat exchange processes at its border.

Źródło:

Structure and Environment; 2017, 9, 1; 59-62
2081-1500

Pojawia się w:

Structure and Environment

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 3.

Tytuł:

Inverse Solution to the Vertical Plate Cooling by Radiation and Convection in Air

Autorzy:

Hadała, Beata
Malinowski, Zbigniew
Gołdasz, Andrzej
Cebo-Rudnicka, Agnieszka

Powiązania:

https://bibliotekanauki.pl/articles/2134090.pdf

Data publikacji:

2022

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

convection heat transfer
radiation heat transfer
plate emissivity
vertical plate

Opis:

The inverse solution to the heat flux identification during the vertical plate cooling in air has been presented. The developed solution allowed to separate the energy absorbed by the chamber due to radiation from the convection heat losses to air. The uncertainty tests were carried out and the accuracy of the solution has been estimated at a level of 1%-5% depending on the boundary condition model. The inverse solution was obtained for the temperature measurements in the vertical plate. The stainless-steel plate was heated to 950°C and then cooled in the chamber in air only to about 30°C. The identified heat transfer coefficient was compared with the Churchill and Chu model. The solution has allowed to separate the radiation heat losses and to determine the Nusselt number values that stay in good agreement with the Churchill and Chu model for a nearly steady-state air flow for the plate temperature below 100°C.

Źródło:

Archives of Metallurgy and Materials; 2022, 67, 3; 1167--1178
1733-3490

Pojawia się w:

Archives of Metallurgy and Materials

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 4.

Tytuł:

Experimental investigation and characteristics of multiwalled carbon nanotube aqua nanofluids from a flat plate heater surface in a pool

Autorzy:

Vasudevan, D.
Senthil Kumar, D.
Murugesan, A.
Vijayakumar, C.

Powiązania:

https://bibliotekanauki.pl/articles/201185.pdf

Data publikacji:

2020

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

nanofluids
critical heat flux
heat transfer coefficient
boiling
heat transfer enhancement

Opis:

In this experimental investigation, the critical heat flux (CHF) of aqua-based multiwalled carbon nanotube (MWCNT) nanofluids at three different volumetric concentrations 0.2%, 0.6%, and 0.8% were prepared, and the test results were compared with deionized water. Different characterization techniques, including X-ray diffraction, scanning electron microscopy and Fourier transform infrared, were used to estimate the size, surface morphology, agglomeration size and chemical nature of MWCNT. The thermal conductivity and viscosity of the MWCNT at three different volumetric concentrations was measured at a different temperature, and results were compared with deionized water. Although, MWCNT-deionized water nanofluid showed superior performance in heat transfer coefficient as compared to the base fluid. However, the results proved that the critical heat flux is increased with an increase in concentrations of nanofluids.

Źródło:

Bulletin of the Polish Academy of Sciences. Technical Sciences; 2020, 68, 3; 547-554
0239-7528

Pojawia się w:

Bulletin of the Polish Academy of Sciences. Technical Sciences

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 5.

Tytuł:

Heat transfer investigations in a liquid that is mixed by means of a multi-ribbon mixer

Autorzy:

Borowski, Tomasz
Sołoducha, Dawid
Musik, Daniel
Wójcik, Krzysztof
Chyla, Mariusz
Ziętarska, Katarzyna
Friedrich, Małgorzata
Kiełbus-Rąpała, Anna
Kordas, Marian
Konopacki, Maciej
Rakoczy, Rafał

Powiązania:

https://bibliotekanauki.pl/articles/1849282.pdf

Data publikacji:

2021

Wydawca:

Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie

Tematy:

multi-ribbon impeller
heat transfer process
heat transfer coefficient
correlation

Opis:

The objective of this paper is to present the investigations of the heat transfer process carried out by means of the multi-ribbon mixer. It is shown that the heat transfer process for the synergic effect of the mixing process and the flowing liquid through the mixer has significantly higher values of the heat transfer coefficients than the mixer with motionless impellers. The empirical correlations between the heat transfer coefficient and the operational parameters obtained in this work can provide guidance for the design and operation of an apparatus equipped with the multi-ribbon impeller. These empirical correlations can be used to predict the heat transfer coefficient for the multi-ribbon mixer.

Źródło:

Polish Journal of Chemical Technology; 2021, 23, 2; 66-72
1509-8117
1899-4741

Pojawia się w:

Polish Journal of Chemical Technology

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 6.

Tytuł:

Determination of heat transfer coefficient in the phase-change heat storage device

Autorzy:

Pavlenko, A. M.
Koshlak, H. V.
Piotrowski, J. Z.

Powiązania:

https://bibliotekanauki.pl/articles/402411.pdf

Data publikacji:

2016

Wydawca:

Politechnika Świętokrzyska w Kielcach. Wydawnictwo PŚw

Tematy:

heat transfer coefficient
heat accumulator

Opis:

This article describes information about the research of the heat transfer coefficient from air to water on the basis of comparison of theoretical calculations with the use of mathematical modeling and experimental studies of small copies of the heat accumulator to operate in the charging mode and discharging process without phase change.

Źródło:

Structure and Environment; 2016, 8, 4; 278-281
2081-1500

Pojawia się w:

Structure and Environment

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 7.

Tytuł:

Numerical verification of two mathematical models for the heat transfer in a laminated rigid conductor
Numeryczna weryfikacja dwóch modeli matematycznych przepływu ciepła dla kompozytów warstwowych

Autorzy:

Łaciński, Ł.

Powiązania:

https://bibliotekanauki.pl/articles/281263.pdf

Data publikacji:

2005

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

heat transfer
laminated conductors

Opis:

Heat transfer problems in composites with a dense periodic structure are usually investigated in the framework of certain averaged (macroscopic) mathematical models. The best known are asymptotic models of periodic heat conductors. The heuristic tolerance models take into account the effect of period lengths on the overall behaviour of a conductor. The purpose of this contribution is to compare the aforementioned models and to verify the obtained solutions to certain benchmark problems.
Do rozwiązywania zagadnień przepływu ciepła w kompozytach o gęstej strukturze periodycznej stosuje się zazwyczaj pewne uśrednione (makroskopowe) modele matematyczne. Najbardziej znanymi modelami ośrodków periodycznych są modele asymptotyczne. Alternatywne heurystyczne modele uwzględniają wpływ periodyki na makroskopowe zachowanie ośrodka. Celem artykułu jest porównanie wspomnianych modeli i weryfikacja uzyskanych rozwiązań numerycznych dla pewnego zagadnienia brzegowo-początkowego.

Źródło:

Journal of Theoretical and Applied Mechanics; 2005, 43, 2; 367-384
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 8.

Tytuł:

Analysis of thermal loads in air cooled SI engine

Autorzy:

Mitianiec, W.
Buczek, K.

Powiązania:

https://bibliotekanauki.pl/articles/246432.pdf

Data publikacji:

2007

Wydawca:

Instytut Techniczny Wojsk Lotniczych

Tematy:

combustion engines
heat transfer

Opis:

In the spark ignition engines with air cooling system the thermal loads of the cylinders and cylinder heads are much bigger than in the water-cooled engines and the loads are not uniform on the whole surface of these elements. Recently most of the cylinders and cylinder heads of the two-wheel vehicles had long ribs that caused a bigger noise and an increase of the mass of the elements. The paper includes the modelling process of the thermal loads and temperature distribution of the cylinder and cylinder head of the two-stroke engine 115 cm3 capacity cooled by air at mean engine load. The results of simulation carried out in ANSYS program with creation of the mesh in CATIA were verified by the experiment on the real engine. The results obtained in the tests and the simulation show, that long ribs have not an effect on the decrease of thermal loads of the cooling elements. The paper includes the colour graphs with deviation of the parts, temperature on the surfaces and thermal stresses. Maun work results allow finding that the cooling heat in the air-cooled two-stroke engine increases with the engine speed and cooling energy, boundary condition enables determine the convection coefficient for heat exchange calculations and FEM enables the prediction of the surface temperatures of the walls, the accuracy of temperature depends on the determination of the outflow temperature of the air.

Źródło:

Journal of KONES; 2007, 14, 3; 403-410
1231-4005
2354-0133

Pojawia się w:

Journal of KONES

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 9.

Tytuł:

An Inverse Approach to Estimate Heat Transfer Coefficients of 122 mm Medium-Range Missile During Correction Engine Operation

Autorzy:

Zmywaczyk, J.
Koniorczyk, P.
Preiskorn, M.
Machowski, B.

Powiązania:

https://bibliotekanauki.pl/articles/403855.pdf

Data publikacji:

2014

Wydawca:

Wojskowa Akademia Techniczna im. Jarosława Dąbrowskiego

Tematy:

heat transfer
thermophysical properties
parameter estimation
R35 steel
heat transfer coefficient

Opis:

This paper presents an inverse approach to estimate the heat transfer coefficients on the inner and the outer sides of a cylindrical shield made of R35 steel containing a gas-dynamic control block of a 122 mm medium-range missile during the combustion of propulsion charge in a correction engine. The specific heat and the thermal diffusivity of R35 steel was experimentally determined using both Netzsch DSC 404F1 Pegasus and LFA 427 measuring devices, respectively. The obtained temperature characteristics of the thermo-physical parameters of cylindrical shield materials were then used to calculate the temperature field concerning the main problem. The inverse problem based on the parameter estimation method using Levenberg–Marquardt optimization procedure was applied to find the unknown heat transfer coefficients. To solve the inverse problem the temperature histories at some locations of the cylindrical shield were known from the experiment. For this purpose a test measuring stand was built and during the combustion process of the propulsion charge inside the cylindrical shield containing the correction engine the temperature distribution on the outer surface of the cylindrical shield was recorded by means of a high-speed infrared camera (PhantomV210). A two-dimensional axial-symmetric nonlinear heat conduction model which takes into account the heat loss due to convection and radiation was solved using the Finite Volume Method (FVM). It was found that the assumption of fixed heat transfer coefficients on both sides of the cylindrical shield was sufficient enough to achieve a satisfactory compliance between the measured and the calculated temperature histories at the same location.

Źródło:

Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa; 2014, 5, 1 (15); 25-39
2081-5891

Pojawia się w:

Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 10.

Tytuł:

On the existence of the sinusoidal-type temperature fluctuations which are independently suppressed by the periodic two-phased conducting layer
O istnieniu sinusoidalnych fluktuacji termicznych tłumionych niezależnie przez dwufazową warstwę kompozytową

Autorzy:

Kula, D.

Powiązania:

https://bibliotekanauki.pl/articles/40195.pdf

Data publikacji:

2015

Wydawca:

Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Wydawnictwo Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie

Tematy:

heat conduction
heat transfer
heat transfer equation
temperature fluctuation
boundary effect behaviour
Fourier expansion

Opis:

The paper describes how to analytically solve hyperbolic system of partial differential equations describing the boundary effect phenomenon, obtained in the framework of the refined tolerance model of heat conduction in periodic composites [Kula and Wierzbicki 2015]. Basic unknowns of this model are coefficients of Fourier expansion representing the temperature field which represents an alternative exact description of the heat transfer in composite rigid conductors. The aim of this paper is to indicate two sinusoidal-type boundary impulses which cannot be transported independently by the two-phased periodic laminated composite. Investigation of the form of the suppression of thermal boundary fluctuations is important to allow the construction to minimize the destruction of composites caused by the rotations of fluctuation amplitudes which are transported by composite not independently.
W artykule opisano, jak rozwiązać analitycznie hiperboliczny układ równań różniczkowych cząstkowych, opisujący zjawisko efektu brzegowego w ramach rozszerzonego tolerancyjnego modelu przewodnictwa ciepła w kompozytach periodycznych [Kula i Wierzbicki 2015]. Podstawowymi niewiadomymi tego modelu są współczynniki rozwinięcia pola temperatury w szereg Fouriera. Szereg ten jest dokładnym rozwiązaniem równania przewodnictwa ciepła. Celem niniejszego artykułu jest wykazanie, że trzy sinusoidalne impulsy brzegowe, pochodzące z tego samego pakietu fluktuacji wybranego spośród nieskończonej rodziny pakietów tworzących układ bazowy Fouriera, są transportowane niezależnie do wnętrza dwuskładnikowego periodycznego przewodnika laminowanego. Badanie tego typu zjawiska pozwala na odpowiedź na pytanie, jaka powinna być budowa geometryczna kompozytu, by nie dopuszczała do powstawania rotacji amplitud fluktuacji przenoszonych przez kompozyty zależnie od siebie. Rotacje te są prawdopodobnie najistotniejszą przyczyną niszczenia kompozytów podczas ich eksploatacji.

Źródło:

Acta Scientiarum Polonorum. Architectura; 2015, 14, 4
1644-0633

Pojawia się w:

Acta Scientiarum Polonorum. Architectura

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 11.

Tytuł:

Badanie wymiany ciepła podczas wrzenia w przepływie czynników roboczych - FC-72 i wody destylowanej w minikanałach
Flow boiling heat transfer in minichannels with FC-72 and distilled water as working fluids

Autorzy:

Strąk, K.
Piasecka, M.

Powiązania:

https://bibliotekanauki.pl/articles/249898.pdf

Data publikacji:

2016

Wydawca:

Instytut Naukowo-Wydawniczy TTS

Tematy:

minikanał
wymiana ciepła
współczynnik przejmowanie ciepła
heat transfer
coefficient of heat transfer
minichannel

Opis:

W artykule zestawiono wartości lokalnych współczynników przejmowania ciepła uzyskane z badań wymiany ciepła podczas przepływu czynnika chłodniczego FC-72 i wody destylowanej przez pionowy minikanał podczas zmiany przepływu. Minikanał posiadał wymiary: głębokość - 1,7 mm, szerokość - 16 mm, długość - 180 mm oraz był ogrzewany asymetrycznie. Elementem grzejnym była płyta grzejna z super stopu Haynes - 230 o grubości 0,45 mm. Lokalne współczynniki przejmowania ciepła wyznaczono na styku ciecz wrząca - powierzchnia grzejna z warunku brzegowego trzeciego rodzaju, przy wykorzystaniu metody jednowymiarowej. Temperatura powierzchni na zewnętrznej powierzchni grzejnej stykającej się bezpośrednio z otoczeniem rejestrowana była za pomocą termowizji (IRT). Płyta szklana stanowiąca drugą ściankę kanału pozwoliła na jednoczesną obserwację struktur przepływu dwufazowego. W pracy omówiono i pokazano stanowisko pomiarowe z jego obiegami i systemami. Przedstawiono przegląd literatury dotyczący zastosowania różnych czynników roboczych w badaniach innych naukowców. Zestawiono i przeanalizowano uzyskane zależności współczynnika przejmowania ciepła w funkcji odległości od wlotu do wylotu minikanału podczas zwiększania strumienia ciepła i skonstruowano krzywe wrzenia, otrzymane na podstawie badań z wykorzystaniem dwóch czynników roboczych: FC-72 i wody destylowanej, przy uzmiennianiu natężenia przepływu. Porównano uzyskane wyniki oraz zarejestrowane struktury wrzenia.
The present paper compares local heat transfer coefficients obtained from the study of flow boiling heat transfer with FC-72 and distilled water in a vertical, asymmetrically heated minichannel at variate flow rate. The minichannel dimensions were as follows: depth – 1.7 mm, width - 16 mm, length - 180 mm. A 0.45 mm thick Haynes-230 plate was the heating element. The local heat transfer coefficients were determined by the one-dimensional method from the third type boundary condition at the interface between the boiling liquid and the heated surface. The temperature at the external face of the heated surface in direct contact with the ambient was registered with infrared thermography (IRT). One of the minichannel walls was made of a glass pane, thus allowing observations of two-phase flow structures. The measurement setup with its circuits and systems was described in detail. The literature review focused on the use of different working fluids in the studies conducted by other researchers. The dependencies of the heat transfer coefficient as a function of the distance from the inlet to the outlet of the minichannel at increasing heat flux were compared and analysed. Boiling curves obtained based on the studies with FC-72 and distilled water were plotted for variated flow rate. The results and recorded boiling structures were compared.

Źródło:

TTS Technika Transportu Szynowego; 2016, 12; 239-245
1232-3829
2543-5728

Pojawia się w:

TTS Technika Transportu Szynowego

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 12.

Tytuł:

Estimation of the influence of inflow turbulence on heat convection from a sphere surface
Oszacowanie wpływu turbulencji napływu na konwekcję ciepła z powierzchni kuli

Autorzy:

Bogusławski, L.

Powiązania:

https://bibliotekanauki.pl/articles/279177.pdf

Data publikacji:

2007

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

convective heat transfer
turbulence
sphere

Opis:

In the paper, results of an experimental investigation of a heat transfer coefficient on a sphere for different inflow turbulence levels have been presented. The average heat transfer coefficient on the sphere surface appear to be dependent on the turbulence level of flow around the sphere. This effect of influence of the flow structure near the sphere surface on the heat transfer process have been presented. Distributions of heat transfer on spheres of different diameters for different turbulence levels of the inflow have been analyzed. It has been shown that an increase of the inflow turbulence level caused an increase of the average heat transfer coefficient on the sphere surface. The maximum increase of the heat transfer due to growing turbulence has been found to be about 30%.
W pracy przedstawiono wyniki badań eksperymentalnych współczynników przejmowania ciepła na kuli przy różnych stopniach turbulencji napływającej strugi. Średni współczynnik przejmowania ciepła na powierzchni kuli jest zależny od stopnia turbulencji przepływu wokół kuli. Jest to rezultat zmiany struktury przepływu w pobliżu ścianki kuli wpływającej na procesy transportu ciepła. Przeprowadzono analizę wymiany ciepła na kulach o różnych średnicach przy zmianie stopnia turbulencji napływającej strugi. Wzrost stopnia turbulencji napływu powoduje wzrost średniego współczynnika przejmowania ciepła na powierzchni kuli. Maksymalny wzrost wymiany ciepła spowodowany wzrostem turbulencji przepływu był rzędu 30%.

Źródło:

Journal of Theoretical and Applied Mechanics; 2007, 45, 3; 505-511
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 13.

Tytuł:

A macroscopic model for the heat transfer in the chessboard-type nonhomogeneous media
Makroskopowy model przewodnictwa ciepła w niejednorodnym ośrodku typu szachownicy

Autorzy:

Wierzbicki, E.

Powiązania:

https://bibliotekanauki.pl/articles/281510.pdf

Data publikacji:

2002

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

heat transfer
nonhomogeneous media
modelling

Opis:

The aim of this paper is to formulate, discuss and apply a certain macroscopic model of the heat transfer in the rigid chessboard-type microinhomogeneous conductor. To this end the tolerance averaging approach is applied. Within the framework of this approach a certain approximate solution to the periodic cell problem is proposed. It leads to the initial-boudary value problem for the averaged temperature field coupled with the initial value problem for the so-called internal variable vector field. In contrast to homogenization, the obtained model describes the effect of mocrostructure size on the overall behaviour of the medium. It is shown that the proposed model has a physical sense provided that the inhomogeneity of the medium is not too large.
Celem pracy jest opracowanie, dyskusja i zastosowanie makroskopowego modelu przewodnictwa ciepła w przewodniku posiadającym periodyczną mikroniejednorodną strukturę typu szachownicy. Stosując technikę tolerancyjnego uśredniania zaproponowano pewne przybliżone rowiązanie zagadnienia na komórce. Rozwiązanie to prowadzi do zagadnienia początkowo-brzegowego dla uśrednionego pola temperatury i sprzężonego z tym problemem zagadnienia początkowego dla pola wektorowego zmiennych wewnętrznych.W przeciwieństwie do homogenizacji otrzymany model opisuje wpływ wymiaru charakterystycznego komórki periodyczności na makroskopowe właściwości ciała. Wykazano, że zaproponowany model ma sens fizyczny, jeżeli niejednorodność ośrodka typu szachownicy jest niezbyt duża.

Źródło:

Journal of Theoretical and Applied Mechanics; 2002, 40, 1; 291-306
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 14.

Tytuł:

Numerical modelling of heat transfer in spherical domains by means of the BEM using discretisation in time
Model numeryczny przepływu ciepła w obszarach sferycznych z wykorzystaniem kombinowanej metody elementów brzegowych

Autorzy:

Mochnacki, B.
Szopa, R.

Powiązania:

https://bibliotekanauki.pl/articles/281477.pdf

Data publikacji:

2002

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

heat transfer
boundary element method

Opis:

A combined variant of the BEM called in literature the BEM using discretization in time consists in an approximation of the time derivative appearing in Fourier's equation by an adequate differential quotient. The next steps of mathematical manipulations and also the numerical algorithm are similar to a typical boudary element approach. In the paper the method is applied to numerical computations concerning a non-steady heat diffusion in homogeneous and non-homogeneous spherical domains. In the final part of the paper the results of computations are presented.
Kombinowany wariant metody elementów skończonych, nazywany w literaturze MEB, z dyskretyzacją czasu polega na zastąpieniu występującej w równaniu Fouriera pochodnej temperatury po czasie odpowiednim ilorazem różnicowym. Dalsze etapy przekształceń matematycznych i konstrukcji algorytmu numerycznego nie odbiegają od typowego podejścia charakteryzującego klasyczną metodę elementów brzegowych. W pracy metodę kombinowaną wykorzystano do modelowania nieustalonej dyfuzji ciepła w obszarach sferycznych jednorodnych i niejednorodnych. W końcowej części przedstawiono przykłady obliczeń numerycznych.

Źródło:

Journal of Theoretical and Applied Mechanics; 2002, 40, 2; 357-370
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 15.

Tytuł:

Experimental analysis of gravitational heat pipe using R507 as a working fluid

Autorzy:

Wojtasik, K.
Zajączkowski, B.

Powiązania:

https://bibliotekanauki.pl/articles/1818146.pdf

Data publikacji:

2016

Wydawca:

Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej

Tematy:

thermosyphon
mathematical model
heat transfer

Opis:

The paper presents possibility of using R507 as a working fluid in gravitational heat pipe. The outcome of experimental analysis are compared to the results obtained with mathematical model. The simulations allow to calculate fluid and wall temperatures in the thermosyphon. The model equations contain the formulas for boiling and condensing heat transfer coefficients. Proposed new model is in good agreement with real operation of the device, especially at the steady state. There are discrepancies during the start-up process, but the differences between the results obtained by the model and experiments do not exceed 5% at the steady state. The thermal efficiency of the thermosyphon is also determined as 0.63.

Źródło:

Zeszyty Energetyczne; 2016, 3; 23--32
2658-0799

Pojawia się w:

Zeszyty Energetyczne

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 16.

Tytuł:

Surface Imaging of Temperature – Research Method of Heat Transfer

Autorzy:

Szafran, Krzysztof
Łusiak, Tomasz
Jeziorek, Łukasz
Korzec, Izabela

Powiązania:

https://bibliotekanauki.pl/articles/2201889.pdf

Data publikacji:

2023

Wydawca:

Stowarzyszenie Inżynierów i Techników Mechaników Polskich

Tematy:

heat transfer
temperature
surface imaging

Opis:

The method does not differ in difficulty from the standard surface temperature imaging method, which is its unquestionable advantage. The disadvantage is the need to use test models made of materials transmitting visible light in the full range (blue light for excitation and red as a recorded result), which, with more complex shapes, makes the model more expensive. Nevertheless, the presented method is a valuable supplement to the set of methods and techniques used so far for imaging temperature fields and estimating the heat flux in the steady state.

Źródło:

Advances in Science and Technology. Research Journal; 2023, 17, 1; 243--251
2299-8624

Pojawia się w:

Advances in Science and Technology. Research Journal

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 17.

Tytuł:

Possibilities of heat transfer augmentation in heat exchangers with minichannels for marine applications

Autorzy:

Mikielewicz, D.
Wajs, J.

Powiązania:

https://bibliotekanauki.pl/articles/258932.pdf

Data publikacji:

2017

Wydawca:

Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa

Tematy:

heat transfer intensification
heat exchangers
pumping power

Opis:

In the paper, new trends in the development of microchannel heat exchangers are presented. The exchangers developed in this way can be applied in marine industry. Main attention is focused on heat exchanger design with reduced size of passages, namely based on microchannels. In authors’ opinion, future development of high power heat exchangers will be based on networks of micro heat exchangers.

Źródło:

Polish Maritime Research; 2017, S 1; 133-140
1233-2585

Pojawia się w:

Polish Maritime Research

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 18.

Tytuł:

Surface localized heat transfer in periodic composites

Autorzy:

Kula, Dorota
Wierzbicki, Ewaryst

Powiązania:

https://bibliotekanauki.pl/articles/386354.pdf

Data publikacji:

2019

Wydawca:

Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej

Tematy:

heat transfer
periodic composites
homogenized model

Opis:

A characteristic feature of the description of physical phenomena formulated by an appropriate boundary or initial-boundary value problem and occurring in microstructured materials is the investigation of the unknown field in the form of decomposition referred to as micro-macro hypothesis. The first term of this decomposition is usually the integral average of the unknown physical field. The second term is a certain disturbance imposed on the first term and is represented in the form of a finite or infinite number of singleton fluctuations. Mentioned expansion is usually referred to as a two-scale expansion of the unknown physical field. In the paper, we purpose to apply two-scale expansion in the form of a certain Fourier series as a result of an applying Surface Localization of the unknown field. The considerations are illustrated by two examples, which results in analytical approximated solutions to the Effective Heat Conduction Problem for periodic composites, including the full dependence on the microstructure length parameter.

Źródło:

Acta Mechanica et Automatica; 2019, 13, 2; 124-129
1898-4088
2300-5319

Pojawia się w:

Acta Mechanica et Automatica

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 19.

Tytuł:

Optimization of heat transfer oriented surfaces by thermovision and using CFD method

Autorzy:

Kapjor, A.
Smatanová, H.
Hužvár, J.
Greššak, T.
Jandačka, J.

Powiązania:

https://bibliotekanauki.pl/articles/402248.pdf

Data publikacji:

2013

Wydawca:

Politechnika Świętokrzyska w Kielcach. Wydawnictwo PŚw

Tematy:

heat transfer
natural convection
CFD method

Opis:

The paper presents applications of infrared measurements. It discusses the use of thermovision and CFD method in the analysis of heat transfer in experimental measurement with natural convection.

Źródło:

Structure and Environment; 2013, 5, 4; 41-44
2081-1500

Pojawia się w:

Structure and Environment

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 20.

Tytuł:

Experimental and theoretical study of surface cooling using a single microjet

Autorzy:

Mikielewicz, D.
Muszyński, T.

Powiązania:

https://bibliotekanauki.pl/articles/175373.pdf

Data publikacji:

2010

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

surface cooling
microjets
heat transfer intensification

Opis:

The experimental research of heat transfer due to impingement of a single microjet of water and air has been studied on a specially designed rig. Systematic data on radial wall temperature distribution were collected, which enabled development of empirical correlation for heat transfer coefficient applicable both for air and water flows. Two microjet nozzle diameters were studied, i.e. 180 and 260 ěm. The correlation describing the heat transfer coefficient was later used in validation of a model of a single microjet impinging on a flat plate, developed earlier by the authors. Such analytical model of microjet is of a great value in future analysis as it enables to carry out for example sensitivity tests or to appropriately select operational parameters. The presented model is quite general and its further modifications are possible when some of the imposed assumptions are relaxed. More experiments on the structure of a single microjet are needed which will confirm the correlation presented in the paper.

Źródło:

Transactions of the Institute of Fluid-Flow Machinery; 2010, 122; 95-110
0079-3205

Pojawia się w:

Transactions of the Institute of Fluid-Flow Machinery

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 21.

Tytuł:

Nucleate pool boiling heat transfer from small horizontal smooth tube bundles

Autorzy:

Krasowski, K.
Cieśliński, J.

Powiązania:

https://bibliotekanauki.pl/articles/175416.pdf

Data publikacji:

2011

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

boiling heat transfer
smooth tube bundle

Opis:

Measurements of boiling heat transfer coefficients in water, methanol and refrigerant R141b are reported for the bundles of smooth tubes that represent a portion of a flooded-type evaporator. Each bundle contained 19 instrumented, electrically heated tubes in a staggered triangular-pitch layout. The effect of heat flux, tube pitch and operating pressure is studied in the paper. Bundle factor and bundle effect are discussed as well. A correlation for prediction of a bundle average heat transfer coefficient is proposed.

Źródło:

Transactions of the Institute of Fluid-Flow Machinery; 2011, 123; 85-97
0079-3205

Pojawia się w:

Transactions of the Institute of Fluid-Flow Machinery

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 22.

Tytuł:

Study of heat transfer parameters on rhodium target for 103Pd production

Autorzy:

Sadeghi, M.
Tenreiro, C.
Van den Winkel, P.

Powiązania:

https://bibliotekanauki.pl/articles/148100.pdf

Data publikacji:

2009

Wydawca:

Instytut Chemii i Techniki Jądrowej

Tematy:

heat transfer
103Pd
rhodium
target

Opis:

The efficiency of cooling and the particle beam characteristics are important when high beam current irradiations are intended for production of radionuclides. The efficiency of cooling is determined by both the target carrier geometry and the flow rate of coolant, while the beam characteristics deal with the current density distribution on the irradiated surface area. Heat transfer on rhodium target to produce 103Pd via the 103Rh(p,n)103Pd reaction was investigated and the beam current was obtained more than 500 mi A.

Źródło:

Nukleonika; 2009, 54, 3; 169-173
0029-5922
1508-5791

Pojawia się w:

Nukleonika

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 23.

Tytuł:

Comparison of methods for solving the heat transfer in electrical machines

Autorzy:

Makki, Z.
Janda, M.
Deeb, R.

Powiązania:

https://bibliotekanauki.pl/articles/377726.pdf

Data publikacji:

2013

Wydawca:

Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej

Tematy:

electrical machines
heat transfer
ANSYS Workbench

Opis:

This paper describes the use of modern computational methods for the verification of mathematical equations, to determine the total heat flow transmitted across a certain surface. ANSYS WORKBENCH is choosen as the computational software for this purpose. Calculations are presented for four models. There is a surface, which the total heat flow is transmitted through is considered as: a simple flat plate, comprising with other flat plate, and thin-walled and thick-walled tube. For each case, the total heat flow is calculated using numerical methods and modem computer methods (ANSYS WORBENCH). Performed results of numerical methods are compared with the results of ANSYS software. The numerical methods are considered as a referent. The error of ANSYS calculations in comparison with the the numerical is calculated. The heat transfer by conduction is described for all presented models. Finally, the results of temperature distribution and heat flux distribution for each simulated case are presented.

Źródło:

Poznan University of Technology Academic Journals. Electrical Engineering; 2013, 75; 25-31
1897-0737

Pojawia się w:

Poznan University of Technology Academic Journals. Electrical Engineering

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 24.

Tytuł:

Damage effect on thermo-mechanical fields in a mid-thick plate

Autorzy:

Ganczarski, A.
Skrzypek, J.

Powiązania:

https://bibliotekanauki.pl/articles/279852.pdf

Data publikacji:

2000

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

continuum damage
heat transfer
Reissner's plate

Opis:

The paper aims at the analysis of damage mechanisms and its influence on heat flow in a mid-thick Reissner's plate. Adapting the concept of thermodamage coupling in continuum damage mechanics, following two 2D coupled problems are formulated: heat transfer through nonhomogeneous partly damaged material and Reissner's membrane-plate made of aluminium alloy, subjected to brittle damage resulting from mechanical and thermal loadings.
Wpływ uszkodzeń na pola termo-mechaniczne w płycie średniej grubości Przedmiotem pracy jest analiza mechanizmów rozwoju uszkodzeń i ich wpływ na przepływ ciepła w płycie Reissner'a sredniej grubości. Stosując sprzężenie efektów termicznych i uszkodzeń w kontynualnej mechanice zniszczenia rozpatruje się następujące dwuwymiarowe zagadnienia pól sprzężonych: transport ciepła w niejednorodnej, częściowo uszkodzonej, aluminiowej płyto-tarczy typu Reissner'a podlegającej kruchemu uszkodzeniu w warunkach złożonych obciążeń termo-mechanicznych.

Źródło:

Journal of Theoretical and Applied Mechanics; 2000, 38, 2; 271-284
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 25.

Tytuł:

Analysis of thermal processes occuring in tissue with a tumor region using bem
Wykorzystanie MEB do analizy procesów cieplnych w tkance zaatakowanej nowotworem.

Autorzy:

Majchrzak, E.
Mochnacki, B.

Powiązania:

https://bibliotekanauki.pl/articles/282077.pdf

Data publikacji:

2002

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

bio-heat transfer
boundary element method

Opis:

In the paper a numerical algorithm based on the boundary element method is used for temperature field computations in the non-homogeneous domain being a composition of healthy tissue and a tumor region. Thermophysical parameters of subdomains, in particular the perfusion coefficients and metabolic heat sources are different. From the mathematical point of view the problem is described by a system of two Poisson's equations with temperature-dependent source functions. These equations are supplemented by adequate boundary conditions. The discussed algorithm allows one to determine the temperature distribution on the surface of the skin. In this way it is possible to analyse the dependence brtween the geometrical features of the tumor region and the external thermal effects. The results can be useful as the information for noninvasive diagnostics. In the final part of the paper examples of computations are shown.
Algorytm numeryczny bazujący na metodzie elementów brzegowych wykorzystano do obliczeń rozkładów remperatury w obszarze niejednorodnym, składającym się ze zdrowej tkanki i podobszaru nowotworowego. Parametry termofizyczne tych podobszarów są zróżnicowane, a w szczególności różnią się współczynniki perfuzji krwi oraz składniki źródłowe związane z metabolizmem. Z matematycznego punktu widzenia rozważane zagadnienie opisane jest układem dwóch równań z zależnymi od temperatury składnikami źródłowymi. Równania te uzupełniają odpowiednie warunki brzegowe. Przedstawiony algorytm pozwala określić rozkład temperatury na powierzchni tkanki skórnej. W ten sposób można analizować zależności między wielkością, kształtem i położeniem podobszaru nowotworowego, a zewnętrznymi efektami termicznymi. Uzyskane wyniki mogą być przydatne w diagnostyce nieinwazyjnej. W końcowej części artykułu przedstawiono przykłady obliczeń.

Źródło:

Journal of Theoretical and Applied Mechanics; 2002, 40, 1; 101-112
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 26.

Tytuł:

Investigation of heat transfer in integrated circuits

Autorzy:

Frankiewicz, M.
Gołda, A.
Kos, A.

Powiązania:

https://bibliotekanauki.pl/articles/220533.pdf

Data publikacji:

2014

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

temperature
heat transfer
VLSI
electric analogy

Opis:

The paper analyzes the phenomenon of heat transfer and its inertia in solids. The influence of this effect on the operation of an integrated circuit is described. The phenomenon is explained using thermal analogy implemented in the Spice environment by an R-C thermal model. Results from the model are verified by some measurements with a chip designed in CMOS 0.7 μm (5 V) technology. The microcontroller-based measurement system structure and experiment results are described.

Źródło:

Metrology and Measurement Systems; 2014, 21, 1; 111-120
0860-8229

Pojawia się w:

Metrology and Measurement Systems

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 27.

Tytuł:

Optimization of a Multi-Drilling Sequence with MQL Supply to Minimize Thermal Distortion of Aluminum Parts

Autorzy:

Faverjon, P.
Rech, J.
Valiorgue, F.
Orsetti, M.

Powiązania:

https://bibliotekanauki.pl/articles/99685.pdf

Data publikacji:

2015

Wydawca:

Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych

Tematy:

thermal distortion
heat transfer
modelling
drilling

Opis:

The drilling process with solid carbide tools with minimum quantity lubrication is under development in the automotive industry due to its high productivity and its environmental benefit. Because of the poor cooling performance when using MQL, a high amount of heat remains in the workpiece, which induces macroscopic thermal distortions and inaccurate parts. This paper presents a methodology to model the thermal distortion of a complex part having a large number of holes. The heat flux entering into the workpiece during each drilling operation is calibrated based on embedded thermocouples and on geometrical observations of the drill surface. Finally, it is shown how the model enables the optimization of a drilling sequence so as to minimize the thermal distortion and the accuracy of the machined part.

Źródło:

Journal of Machine Engineering; 2015, 15, 3; 75-89
1895-7595
2391-8071

Pojawia się w:

Journal of Machine Engineering

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 28.

Tytuł:

Wyznaczanie podstawowych parametrów wymiany ciepła w stanach przejściowych pracy ogrzewacza wody
Determination of the basic parameters heat transfer coefficient in transient conditions of water heater

Autorzy:

Chamera, S.
Łyczko, M.

Powiązania:

https://bibliotekanauki.pl/articles/152985.pdf

Data publikacji:

2014

Wydawca:

Stowarzyszenie Inżynierów i Techników Mechaników Polskich

Tematy:

przepływowy ogrzewacz wody
współczynnik przejmowania ciepła
wymiana ciepła
instantaneous water heater
heat transfer coefficient
heat transfer

Opis:

W artykule przedstawiono problem wyznaczania współczynnika przejmowania ciepła z powierzchni grzałek do przepływającej wody w stanach przejściowych pracy przepływowego ogrzewacza wody. Znajomość poprawnej wartości tego współczynnika pozwala na szybsze osiągnięcie przez ogrzewacz żądanych nastaw temperatury. Przynosi to wymierne korzyści w postaci niższego zużycia energii przez urządzenie. Współczynnik przejmowania ciepła wyznaczono minimalizując sumę kwadratów odchyłek pomiędzy wartościami wynikającymi z modelu matematycznego a wartościami wynikającymi z pomiarów wykonanych na rzeczywistym urządzeniu. Przedstawiono na wykresach również kilka przykładowych stanów przejściowych pracy ogrzewacza przy wybranych parametrach.
The paper presents the problem of determining the heat transfer coefficient from heating elements to flowing water in transient conditions of instantaneous water heater. This parameter is important in terms of proper system control, knowledge of its correct value allows the heater to achieve the desired settings faster. It brings measurable benefits, as lower energy consumption. Changing the value of water flow and power, transient conditions for the different parameters of the water heater were observed and measured. Mathematical model of the heating system was created with some assumptions and simplifications. An analysis of the results of measurements was done and the heat transfer coefficient was determined by minimizing the mean squared errors between the values resulting from the mathematical model and measurements made on a real device. Some examples of transient water heater conditions are shown in the diagrams.

Źródło:

Pomiary Automatyka Kontrola; 2014, R. 60, nr 12, 12; 1232-1234
0032-4140

Pojawia się w:

Pomiary Automatyka Kontrola

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 29.

Tytuł:

Analysis of heat and mass transfer in an adsorption bed using CFD methods

Autorzy:

Janusz, Szymon
Szudarek, Maciej
Rudniak, Leszek
Borcuch, Marcin

Powiązania:

https://bibliotekanauki.pl/articles/27312232.pdf

Data publikacji:

2023

Wydawca:

Polska Akademia Nauk. Czasopisma i Monografie PAN

Tematy:

heat transfer
adsorption
CFD
mass transfer
refrigeration devices

Opis:

The trend of reducing electricity consumption and environmental protection has contributed to the development of refrigeration technologies based on the thermal effect of adsorption. This article proposes a methodology for conducting numerical simulations of the adsorption and desorption processes. Experimental data available in the literature were used as guidelines for building and verifying the model, and the calculations were carried out using commercial computational fluid dynamics software. The simulation results determined the amount of water vapor absorbed by the adsorbent bed and the heat generated during the adsorption process. Throughout the adsorption process, the inlet water vapor velocity, temperature, and pressure in the adsorbent bed were monitored and recorded. The results obtained were consistent with the theory in the literature and will serve as the basis for further, independent experimental studies. The validated model allowed for the analysis of the effect of cooling water temperature on the sorption capacity of the material and the effect of heating water temperature on bed regeneration. The proposed approach can be useful in analyzing adsorption processes in refrigeration applications and designing heat and mass exchangers used in adsorption systems.

Źródło:

Archives of Thermodynamics; 2023, 44, 2; 177--194
1231-0956
2083-6023

Pojawia się w:

Archives of Thermodynamics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 30.

Tytuł:

Experimental determination of the working fluid volume for optimal function of the loop heat pipe

Autorzy:

Hrabovský, P.
Nemec, P.
Malcho, M.
Jandačka, J.

Powiązania:

https://bibliotekanauki.pl/articles/402058.pdf

Data publikacji:

2013

Wydawca:

Politechnika Świętokrzyska w Kielcach. Wydawnictwo PŚw

Tematy:

loop heat pipe
heat transfer
cooling
working fluid

Opis:

This experiment is concentrated on the working fluid of the heat pipe. The working fluid is an important part for the function of the heat pipe regarding the transfer of the heat. The measurements point out the appropriate quantity of the working fluid regarding the correct function of the loop heat pipe in the cooling of electronic components.

Źródło:

Structure and Environment; 2013, 5, 4; 29-31
2081-1500

Pojawia się w:

Structure and Environment

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 31.

Tytuł:

Development of ORC’s for micro power generation

Autorzy:

Mikielewicz, Jarosław
Mikielewicz, Dariusz

Powiązania:

https://bibliotekanauki.pl/articles/1191859.pdf

Data publikacji:

2018

Wydawca:

Gdańska Szkoła Wyższa

Tematy:

CHP
ORC
heat exchangers
heat transfer intensification
thermodynamics

Opis:

In the paper, new trends in development of micro power generation of heat and electricity are presented. New type of CHP for domestic usage is developed in the Institute of Fluid-Flow Machinery PAS and methods of its design are presented. The most promising trends in equipment of ORC cycle for this purpose were discussed. Main attention was focused on micro-heat exchangers design based on micro-channels and micro-jets. In our opinion future development of high power heat exchangers will be based on nets micro-heat exchangers.

Źródło:

Eco-Energetics: technologies, environment, law and economy; 2018, 1; 51--72
2657-5922
2657-7674

Pojawia się w:

Eco-Energetics: technologies, environment, law and economy

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 32.

Tytuł:

The effect of the assumed thermophysical properties of steel on the heat transfer calculation result in contact phenomena

Autorzy:

Rywotycki, Marcin
Malinowski, Zbigniew
Przyłucka, Aleksandra
Sołek, Krzysztof

Powiązania:

https://bibliotekanauki.pl/articles/29520236.pdf

Data publikacji:

2020

Wydawca:

Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH

Tematy:

heat transfer
inverse method
solid surface contact

Opis:

The article presents a model of heat transfer between two solid surfaces remaining in contact under the effect of the force applied. The presented results were obtained from the authors’ own studies conducted with the application of a new method of determining the heat flux transferred between these surfaces. The method consists of two stages: the experiment and numerical calculations. The experimental tests include temperature measurements in specific points in two samples remaining in contact with each other. The numerical part uses the inverse solution and the finite element method for the calculation of the heat flux on the contact surface. An analysis was performed on the effect of the steel grade used in the tests on the result of heat transfer determination in contact phenomena. The calculations were conducted with the application of proprietary software using the inverse method integrated with FEM.

Źródło:

Computer Methods in Materials Science; 2020, 20, 4; 165-172
2720-4081
2720-3948

Pojawia się w:

Computer Methods in Materials Science

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 33.

Tytuł:

Mixed convection heat transfer in trapezoidal lid-driven cavity with uniformly heated inner circular cylinder

Autorzy:

Hussein, Asmaa Ali

Powiązania:

https://bibliotekanauki.pl/articles/27312211.pdf

Data publikacji:

2023

Wydawca:

Polska Akademia Nauk. Czasopisma i Monografie PAN

Tematy:

cavity
heat transfer
mixed convection
lid-driven

Opis:

The present work comprises a numerical analysis using the Ansys program to solve the problem of combined free-forced convection around a circular cylinder located in a horizontal lid-driven trapezoidal enclosure. The enclosure is filled with water. The upper moving wall and lower fixed wall are cold at a constant temperature, whereas the inclined walls are adiabatically insulated. The uniformly heated cylinder is located at different positions in the cavity. The study covers three values of Richardson number (0.01, 1, and 10). The results show that the streamlines and isotherms in the enclosure, the Nusselt number and friction factor in the moving wall, hot wall and bottom wall are strongly dependent on the position of the inner hot cylinder. The results are validated with previous work, and the comparison gives good agreement.

Źródło:

Archives of Thermodynamics; 2023, 44, 3; 99--118
1231-0956
2083-6023

Pojawia się w:

Archives of Thermodynamics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 34.

Tytuł:

Adjustment calculus and Trefftz functions applied to local heat transfer coefficient determination in a minichannel
Zastosowanie rachunku wyrównawczego i funkcji Trefftza do wyznaczenia lokalnego współczynnika przejmowania ciepła w minikanale

Autorzy:

Grysa, K.
Hożejowska, S.
Maciejewska, B.

Powiązania:

https://bibliotekanauki.pl/articles/281729.pdf

Data publikacji:

2012

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

flow boiling
liquid crystals
heat transfer coefficient

Opis:

The paper presents results of numerical calculations conducted in order to define the heat transfer coefficient in flow boiling in a vertical minichannel with one side made of a heating foil with liquid crystals. During the experiment, we measured the local temperature of the foil, inlet and outlet liquid temperature and pressure, current and voltage drop of the electric power supplied to the heater. Local measurements of foil temperature were approximated with a linear combination of the Trefftz functions. The known temperature measurement errors allowed application of the adjustment calculus. The foil temperature distribution was determined by the FEM combined with the Trefftz functions. Local heat transfer coefficients between the foil and the boiling fluid were calculated from the third-kind condition.
Przedstawiono wyniki obliczeń numerycznych przeprowadzonych w celu określenia współczynnika przejmowania ciepła przy przepływie wrzącej cieczy w pionowym minikanale, którego jedna ściana wykonana jest z folii grzewczej pokrytej ciekłymi kryształami. Podczas eksperymentu mierzono: lokalną temperaturę folii, temperaturę cieczy na wlocie i wylocie z minikanału, ciśnienie cieczy w minikanale oraz spadek natężenia i napięcia prądu stałego dostarczanej do folii grzewczej. Lokalne pomiary temperatury folii aproksymowano kombinacją liniową funkcji Trefftza. Znane błędy pomiaru temperatury pozwoliły na stosowanie rachunku wyrównawczego. Rozkład temperatury folii został określony przy zastosowaniu MES w powiązaniu z funkcjami Trefftza. Lokalne współczynniki wymiany ciepła pomiędzy folią i wrzącym płynem zostały wyliczone z warunku trzeciego rodzaju.

Źródło:

Journal of Theoretical and Applied Mechanics; 2012, 50, 4; 1087-1096
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 35.

Tytuł:

Numerical simulation of heat flow processes

Autorzy:

Mielewczyk, A.

Powiązania:

https://bibliotekanauki.pl/articles/259531.pdf

Data publikacji:

2005

Wydawca:

Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa

Tematy:

simulation
dynamic model
heat transfer
Z-transform

Opis:

Numerical simulation methodis basedon mathematical models of physical processes, which describe run of a given process with a various accuracy. This paper presents a method for elaborating the computer simulation models based on differential equations. This makes it possible to obtain a high accuracy of representing dynamic features of a real process. The derived results are given in the form of numerical series. An example of modelling the dynamics of heat transfer through aflat wall is presented in the second part of the paper. Basing on the model one can simulate the process of operation of ship engine as well as such auxiliary devices as a cooler, evaporator, condenser, tank heating system etc.

Źródło:

Polish Maritime Research; 2005, 4; 22-25
1233-2585

Pojawia się w:

Polish Maritime Research

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 36.

Tytuł:

Effect of heat transfer on peristaltic flow in presence of heat generation against higher value of Reynolds number using FEM

Autorzy:

Javed, Tariq
Hamid, Abdul H.
Ahmed, Bilal
Ali, Nasir

Powiązania:

https://bibliotekanauki.pl/articles/1839717.pdf

Data publikacji:

2021

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

finite element method
peristaltic flow
heat transfer

Opis:

In the present investigation, heat transfer analysis of peristaltic flow in the presence of heat generation against high values of the Reynolds number using a numerical technique is presented. The Finite Element Method with the assistance of Galerkin’s variational method has been used on the governing Navier-Stokes equation in the stream-vorticity form. The graphs of computed longitudinal velocity, temperature distribution and pressure rise per wavelength are plotted against different values of an emerging parameter using a stream function and vorticity. The presented results are valid beyond the restrictions of long wavelength and low Reynolds number limits. Moreover, large values of the Reynolds number increases pressure rise per wavelength.

Źródło:

Journal of Theoretical and Applied Mechanics; 2021, 59, 2; 279-292
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 37.

Tytuł:

An analysis of coal and coal mine methane co-combustion in an 140 t/h pulverized coal boiler

Autorzy:

Jagodzińska, K.
Hernik, B.
Pronobis, M.

Powiązania:

https://bibliotekanauki.pl/articles/175356.pdf

Data publikacji:

2017

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

Co-combustion
methane
heat transfer
power boiler

Opis:

The paper presents an attempt to evaluate the impact of coal and coal mine methane cocombustion on the physics of the heat exchange in an 140 t/h pulverized-coal boiler through an analysis of 21 combinations of the boiler operating parameters – three different boiler loads (50, 75, and 100%) and seven values of the fired gas thermal contribution (0–60%). The obtained results are the temperature distribution of flue gas and steam in the boiler characteristic points, the heat transfer coefficient values for the boiler individual elements expressing the nature of changes in the heat transfer and the change in the boiler efficiency depending on how much gas is actually fired. An increase in the amount of co-fired gas involves a temperature increase along the flue gas path. This is the effect of the reduction in the amount of heat collected by the evaporator in the furnace. For these reason, the flue gas temperature at the furnace outlet rises by 9 K on average per a 0.1 increment in the fired gas thermal contribution. The temperature rise improves the heat transfer in the boiler heat exchangers – for the first- and the secondstage superheater the improvement totals 2.8% at a 10 pp. increase in the fired gas thermal contribution. However, the rise in the flue gas temperature at the boiler outlet involves a drop in the boiler efficiency (by 0.13 pp. for a rise in the fired gas thermal contribution by 0.1).

Źródło:

Transactions of the Institute of Fluid-Flow Machinery; 2017, 137; 3-18
0079-3205

Pojawia się w:

Transactions of the Institute of Fluid-Flow Machinery

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 38.

Tytuł:

Thermal stresses in the heated wall of the minichannel

Autorzy:

Błasiak, S.
Musiał, T.
Piasecka, M.
Strąk, K.

Powiązania:

https://bibliotekanauki.pl/articles/114583.pdf

Data publikacji:

2016

Wydawca:

Stowarzyszenie Inżynierów i Techników Mechaników Polskich

Tematy:

thermal stress
distortion
minichannel
heat transfer
boiling

Opis:

This paper deals with thermal deformations of the heating foil in a heat exchanger with a rectangular minichannel. Flow boiling heat transfer was achieved to maximize the heat transfer coefficient. As confirmed by the experiments, the deformations resulting from the thermal expansion of the heating foil led to local narrowing of the channel, and consequently distorted flow and less effective heat transfer.

Źródło:

Measurement Automation Monitoring; 2016, 62, 1; 22-25
2450-2855

Pojawia się w:

Measurement Automation Monitoring

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 39.

Tytuł:

Dispersed phase breakup at emulsion boiling

Autorzy:

Klimov, R.
Pavlenko, A.

Powiązania:

https://bibliotekanauki.pl/articles/402264.pdf

Data publikacji:

2017

Wydawca:

Politechnika Świętokrzyska w Kielcach. Wydawnictwo PŚw

Tematy:

heat transfer coefficient
turbulence level
dispersed phase

Opis:

In this paper we consider the breakup processes of the emulsion dispersed phase. The possibility of large droplets splitting by small ones under boiling water phase due to a sharp release of pressure is shown, we also take into account the force impact of one drop on the another, based on the instability criteria of Bond and Weber. It is indicated the applicability of the model to determine the processes of displacement, deformation or breakup of inclusions of dispersed phase.

Źródło:

Structure and Environment; 2017, 9, 1; 63-69
2081-1500

Pojawia się w:

Structure and Environment

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 40.

Tytuł:

An inverse medium problem for the heat equation

Autorzy:

Maponi, P.

Powiązania:

https://bibliotekanauki.pl/articles/1954522.pdf

Data publikacji:

1999

Wydawca:

Politechnika Gdańska

Tematy:

differential equations
heat transfer equations
inverse problem

Opis:

In the article we consider the two-dimensional heat equation in a circular domain where the thermal diffusivity is a piecewise constant function in the radial directon and is a constant function in the angular direction. In particular we consider the problem of computation of a perturbation in this stratified medium having some information/knowledge about the temperature on the boundary of the domain due to heat flux applied to the same boundary. A linearized version of this inverse problem is considered and a linear integral equation is used for the numerical solution of the inverse problem. Some numerical examples are reported.

Źródło:

TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 1999, 3, 3; 277-292
1428-6394

Pojawia się w:

TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 41.

Tytuł:

Modelling of Heat Transfer at the Solid to Solid Interface

Autorzy:

Rywotycki, M.
Malinowski, Z.
Falkus, J.
Sołek, K.
Szajding, A.
Miłkowska-Piszczek, K.

Powiązania:

https://bibliotekanauki.pl/articles/958225.pdf

Data publikacji:

2016

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

heat transfer
inverse method
solid - solid interface

Opis:

In technological process of steel industry heat transfer is a very important factor. Heat transfer plays an essential role especially in rolling and forging processes. Heat flux between a tool and work piece is a function of temperature, pressure and time. A methodology for the determination of the heat transfer at solid to solid interface has been developed. It involves physical experiment and numerical methods. The first one requires measurements of the temperature variations at specified points in the two samples brought into contact. Samples made of C45 and NC6 steels have been employed in physical experiment. One of the samples was heated to an initial temperature of: 800°C, 1000°C and 1100°C. The second sample has been kept at room temperature. The numerical part makes use of the inverse method for calculating the heat flux and at the interface. The method involves the temperature field simulation in the axially symmetrical samples. The objective function is bulled up as a dimensionless error norm between measured and computed temperatures. The variable metric method is employed in the objective function minimization. The heat transfer coefficient variation in time at the boundary surface is approximated by cubic spline functions. The influence of pressure and temperature on the heat flux has been analysed. The problem has been solved by applying the inverse procedure and finite element method for the temperature field simulations. The self-developed software has been used. The simulation results, along with their analysis, have been presented.

Źródło:

Archives of Metallurgy and Materials; 2016, 61, 1; 341-346
1733-3490

Pojawia się w:

Archives of Metallurgy and Materials

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 42.

Tytuł:

The influence of radiation model on the distribution of heat flux in the pusher furnace
Wpływ modelu promieniowania na rozkład gęstości strumienia ciepła w piecu przepychowym

Autorzy:

Gołdasz, A.
Malinowski, Z.
Telejko, T.
Rywotycki, M.
Szajding, A.

Powiązania:

https://bibliotekanauki.pl/articles/356205.pdf

Data publikacji:

2012

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

radiation heat transfer
pusher furnace
charge heating

Opis:

A three dimensional numerical model of the heat exchange during a charge heating process in a pusher furnace, using the finite element method, was used in this study. The radiative heat exchange in the furnace chamber was carried out based on two methods: the zone method and the method of basing on the average configuration ratio. In the zone method the flux of radiation energy reaching the surface of the heated charge was determined by performing calculations of brightness in a multi-surface closed system which is the pusher furnace chamber filled with an emitting-absorbing medium. In the second case an average configuration ratio was used by setting the radiation energy flux through linking the walls temperature with the furnace atmosphere temperature.
W pracy wykorzystano trójwymiarowy model numeryczny wymiany ciepła w czasie nagrzewania wsadu w piecu przepychowym przy zastosowaniu metody elementów skończonych. Radiacyjna wymianę ciepła w komorze pieca realizowano w oparciu o dwie metody: metodę strefowa oraz w oparciu o średni współczynnik konfiguracji. W metodzie strefowej strumień energii radiacyjnej docierającej do powierzchni nagrzewanego wsadu wyznaczano prowadząc obliczenia jasności w wielo-powierzchniowym układzie zamkniętym jakim jest komora pieca przepychowego wypełnionego ośrodkiem emitująco-pochłaniającym. W drugim przypadku wykorzystano średni współczynnik konfiguracji wyznaczając strumie energii radiacyjnej poprzez powiazanie temperatury ścian z temperatura atmosfery pieca.

Źródło:

Archives of Metallurgy and Materials; 2012, 57, 4; 1143-1149
1733-3490

Pojawia się w:

Archives of Metallurgy and Materials

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 43.

Tytuł:

Recovery of microstructure properties: random variability of soil solid thermal conductivity

Autorzy:

Stefaniuk, D.
Różański, A.
Łydżba, D.

Powiązania:

https://bibliotekanauki.pl/articles/178952.pdf

Data publikacji:

2016

Wydawca:

Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej

Tematy:

simulated annealing
heat transfer
homogenization
saturated soil

Opis:

In this work, the complex microstructure of the soil solid, at the microscale, is modeled by prescribing the spatial variability of thermal conductivity coefficient to distinct soil separates. We postulate that the variation of thermal conductivity coefficient of each soil separate can be characterized by some probability density functions: f_Cl(λ), f_Si(λ), f_Sa(λ), for clay, silt and sand separates, respectively. The main goal of the work is to recover/identify these functions with the use of back analysis based on both computational micromechanics and simulated annealing approaches. In other words, the following inverse problem is solved: given the measured overall thermal conductivities of composite soil find the probability density function f(λ) for each soil separate. For that purpose, measured thermal conductivities of 32 soils (of various fabric compositions) at saturation are used. Recovered functions f(λ) are then applied to the computational micromechanics approach; predicted conductivities are in a good agreement with laboratory results.

Źródło:

Studia Geotechnica et Mechanica; 2016, 38, 1; 99-107
0137-6365
2083-831X

Pojawia się w:

Studia Geotechnica et Mechanica

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 44.

Tytuł:

Nanofluid flow and heat transfer of carbon nanotube and graphene platelette nanofluids in entrance region of microchannels

Autorzy:

Fuller, N. E.
Liu, J. T. C.

Powiązania:

https://bibliotekanauki.pl/articles/38606230.pdf

Data publikacji:

2020

Wydawca:

Instytut Podstawowych Problemów Techniki PAN

Tematy:

nanofluids
heat transfer
carbon nanotube
graphene nanoplatelettes

Opis:

Suspensions of nano-scale particles in liquids, dubbed nanofluids, are of great interest for heat transfer applications. Nanofluids potentially offer superior thermal conductivity to alternative, pure fluids and are of particular interest in applications where active cooling of power-dense systems is required. In this work, the thermophysical properties of carbon nanotube nanofluids (CNTNf) and those of graphene nanoplatelette nanofluids (GNPNf) as functions of particle volume fraction are deduced from published experiments. These properties are applied to a perturbative boundary layer model to examine how the velocity and temperature profiles (and correspondingly shear stress and surface heat transfer) vary with the nanoparticle concentration in the entrance region of microchannels. Findings of this modeling effort indicate that both shear stress and heat transfer in GNPNf increase with increasing particle concentration. The normalized increase in shear stress is approximately twice that for heat transfer as a function of the GNP particle concentration. Interestingly, CNTNf shows anti-enhancement heat transfer behaviour; an increasing concentration of CNT nanoparticles is associated with both an increase in shear stress and a decrease in the surface heat transfer rate.

Źródło:

Archives of Mechanics; 2020, 72, 4; 355-379
0373-2029

Pojawia się w:

Archives of Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 45.

Tytuł:

An advanced thermal-FSI approach of an evaporation of air heat pump

Autorzy:

Felicjancik, J.
Ziółkowski, P.
Badur, J.

Powiązania:

https://bibliotekanauki.pl/articles/175437.pdf

Data publikacji:

2015

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

CFD modeling
evaporator
fin-tube heat exchanger
heat transfer

Opis:

The paper presents selected problems of numerical modelling of an advanced thermal- FSI (Fluid solid interaction) approach of evaporator of air heat pump. The example of a fin-tube evaporator has been studied, focusing on obtaining the heat exchanger characteristics applying two-phase flow model for the in-tube refrigerant flow. Special attention is given to heat transfer between separated medium for different air velocity and changed refrigerant mass flow in-tube.

Źródło:

Transactions of the Institute of Fluid-Flow Machinery; 2015, 129; 111-141
0079-3205

Pojawia się w:

Transactions of the Institute of Fluid-Flow Machinery

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 46.

Tytuł:

Mathematical model and measurements of a combi-steamer condensation hood

Autorzy:

Tokarski, Mieszko
Ryfa, Arkadiusz
Buliński, Piotr
Rojczyk, Marek
Ziarko, Krzysztof
Nowak, Andrzej J.

Powiązania:

https://bibliotekanauki.pl/articles/240444.pdf

Data publikacji:

2020

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

energy balance
heat transfer
heat exchanger
condensation
condensation hood

Opis:

Combi-steamer condensation hoods are widely used in modern gastronomy. They condense steam produced by the combi-steamer and also filter solid particles, moisture, grease and smells. All these factors negatively affect the staff and dishes, so efficient work of the condensation hoods becomes important. A mathematical and experimental analysis of such a device is described in this paper. First a measurement methodology was designed and measurements of air humidity, temperature and mass flow rates were performed. The measurement procedure concerned dedicated a steam generator and combi-steamer. Next a mathematical model was developed. It was based on mass and energy balances of the condensation hood. The condensate flow rate turned out to be insufficient to fulfill the energy balance while measured directly. Hence, it was calculated from heater’s power of the steam generator and the balance model was validated. The combisteamer had an unknown output, so the condensate flow rate was provided by the balance model after its validation. A preliminary diagnosis of the device was carried out as well.

Źródło:

Archives of Thermodynamics; 2020, 41, 1; 125-149
1231-0956
2083-6023

Pojawia się w:

Archives of Thermodynamics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 47.

Tytuł:

The results of the experimental research of the heat transfer coefficient during steam condensation in the tubes of the diesel radiator sections
Rezultaty ehksperimenthykh issledovanijj koehfficienta teplootdanykh pri kondensacii para v trubkakh teplovoznykh radiatornykh sekcijj

Autorzy:

Sklifus, Y.
Mohyla, V.

Powiązania:

https://bibliotekanauki.pl/articles/792234.pdf

Data publikacji:

2012

Wydawca:

Komisja Motoryzacji i Energetyki Rolnictwa

Tematy:

experimental research
heat transfer coefficient
heat transfer ratio
diesel locomotive
phase transition
cooling system
power plant
steam condensation

Źródło:

Teka Komisji Motoryzacji i Energetyki Rolnictwa; 2012, 12, 4
1641-7739

Pojawia się w:

Teka Komisji Motoryzacji i Energetyki Rolnictwa

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 48.

Tytuł:

Investigation of a high-forced cooling system for the elements of heat power installations

Autorzy:

Genbach, A. A.
Bondartsev, D. Y.
Iliev, I. K.

Powiązania:

https://bibliotekanauki.pl/articles/100148.pdf

Data publikacji:

2018

Wydawca:

Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych

Tematy:

heat transfer control
capillary-porous coatings
natural mineral media
heat-transfer crisis
capillary-porous system
thermal power plants

Opis:

The studies of the ultimate thermal flows have been carried out in metallic and poorly heat-conducting porous structures, which operate when gravitational and capillary forces act jointly and cool various devices of thermal power plants in order to create a scientific methodology. The mechanism of destruction of metal vaporizing surfaces and poorly heat-conducting coatings of low porosity made of natural mineral media (granite) has been described on the basis of the problem of thermoelasticity and experimental data. Thermal flow dependences on time of their action and depth of penetration of temperature perturbations were identified based on analogy. Capillary-porous systems have high intensity, heat transport ability, reliability, compactness. The results of calculations and experiment showed that the maximum thickness of the particles that detach under the influence of compression forces for granite coatings is (0.25÷0.3).10^-2 m. Sections of compression curves that determine the detachment of particles with dimensions of more than 0.3×10^-2 m for large thermal flows and short feed times, are screened by the melting curve, and in the case of small thermal flows and time intervals – the expansion curve.

Źródło:

Journal of Machine Engineering; 2018, 18, 2; 106-117
1895-7595
2391-8071

Pojawia się w:

Journal of Machine Engineering

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 49.

Tytuł:

Investigation of thermal-flow characteristics of the minichannel heat exchanger of variable louvers height

Autorzy:

Romaniak, Artur
Kowalczyk, Michał Jan
Łęcki, Marcin
Gutkowski, Artur
Górecki, Grzegorz

Powiązania:

https://bibliotekanauki.pl/articles/27312209.pdf

Data publikacji:

2023

Wydawca:

Polska Akademia Nauk. Czasopisma i Monografie PAN

Tematy:

CFD
heat transfer
heat pump
louvered fin
minichannel heat exchanger

Opis:

The numerical simulation of the heat transfer in the flow channels of the minichannel heat exchanger was carried out. The applied model was validated on the experimental stand of an air heat pump. The influence of louver heights was investigated in the range from 0 mm (plain fin) to 7 mm (maximum height). The set of simulations was prepared in Ansys CFX. The research was carried out in a range of air inlet velocities from 1 to 5 m/s. The values of the Reynolds number achieved in the experimental tests ranged from 93 to 486. The dimensionless factors, the Colburn factor and friction factor, were calculated to evaluate heat transfer and pressure loss, respectively. The effectiveness of each louver height was evaluated using the parameter that relates to the heat transfer and the pressure drop in the airflow. The highest value of effectiveness (1.53) was achieved by the louver height of 7 mm for the Reynolds number of around 290.

Źródło:

Archives of Thermodynamics; 2023, 44, 3; 119--141
1231-0956
2083-6023

Pojawia się w:

Archives of Thermodynamics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 50.

Tytuł:

The influence of coolant velocity on the local heat transfer coefficient during steel quenching

Autorzy:

Szajding, Artur
Gołdasz, Andrzej
Telejko, Tadeusz

Powiązania:

https://bibliotekanauki.pl/articles/29520233.pdf

Data publikacji:

2020

Wydawca:

Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH

Tematy:

inverse method
heat transfer coefficient
boundary condition
quenching

Opis:

The results of the calculations of the local heat transfer coefficient HTC and a heat flux HF on the face of a cylindrical sample made of 1.0503 steel are presented. The sample was cooled from a temperature of approx. 930°C in a mineral oil having a temperature equal to 50°C. The experiments were performed for three speeds of the oil stream (0.2, 0.4 and 0.6 m/s). The oil stream was directed perpendicularly to the cooled surface. The temperature of each sample was measured with 4 thermocouples and recorded with a frequency of 10 Hz. The maximum values of HTC always occurred in the axis of the sample and were in the range of 8000 to 10,000 W/(m² K). The results are presented in the form of useful graphs showing the dependence of HTC and HF on the surface temperature for various velocities of cooling oil. The calculations were made with self-developed software using the inverse solution of the boundary heat conduction problem.

Źródło:

Computer Methods in Materials Science; 2020, 20, 4; 157-164
2720-4081
2720-3948

Pojawia się w:

Computer Methods in Materials Science

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 51.

Tytuł:

Non-isothermal constitutive relations and heat transfer equations of a two-phase medium

Autorzy:

Uciechowska-Grakowicz, A.
Strzelecki, T.

Powiązania:

https://bibliotekanauki.pl/articles/178714.pdf

Data publikacji:

2017

Wydawca:

Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej

Tematy:

heat transfer
porous media
thermal consolidation
constitutive equations

Opis:

In the case of a two-phase medium – such as the soil, which consists of an elastic skeleton and is filled with pore fluids – stress and strain within the medium are dependent on both phases. Similarly, in the case of heat transfer, heat is conducted through the two phases at different rates, with an additional heat transfer between the phases. In the classical approach to modelling a porous medium, it is assumed that the fluid filling the pore space is water, which is incompressible. In the case of gas, the volume of which is strongly dependent on temperature and pressure, one should take this behavior into account in the constitutive relations for the medium. This work defines the physical relations of a two-phase medium and provides heat transfer equations, constructed for a porous, elastic skeleton with fluid-filled pores, which may be: liquid, gas, or mixture of liquid and a gas in non-isothermal conditions. The paper will present constitutive relations derived from the laws of irreversible thermodynamics, assuming that pores are filled with either a liquid or a gas. These relations, in the opinion of the authors, may be used as the basis for the construction of a model of the medium filled partly with a liquid and partly with a gas. It includes the possibility of independent heat transfer through any given two-phase medium phase, with the transfer of heat between the phases.

Źródło:

Studia Geotechnica et Mechanica; 2017, 39, 3; 67-78
0137-6365
2083-831X

Pojawia się w:

Studia Geotechnica et Mechanica

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 52.

Tytuł:

Numerical investigation of local heat transfer distribution on surfaces with a non-uniform temperature under an array of impinging jets with various nozzle shapes

Autorzy:

Marzec, K.
Kucaba-Piętal, A.

Powiązania:

https://bibliotekanauki.pl/articles/279593.pdf

Data publikacji:

2017

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

impinging jet
heat transfer
Nusselt number
nozzle shape

Opis:

Numerical calculations of heat transfer characteristics of an impingement cooling system with a non-uniform temperature on a cooled surface using ANSYS CFX have been performed. The influence of a surface heat flux q_w(x) and a nozzle shape on the Nusselt number distribution on the cooled surface has been studied. The setup consisted of a cylindrical plenum with an inline array of ten impingement jets. Cylindrical, convergent divergent shapes of nozzles and linear temperature distribution on the cooled surface have been considered for various heat fluxes q_w (x). Results indicate that geometry of the cylindrical nozzles resulted in the highest Nusselt numbers along the cooled surface. The line of the averaged Nusselt number has a trend to increase in the direction of the flow for the cooling system with increasing values of the surface heat flux q(x). This tendency can be observed for all presented shapes of jets. On the other hand, for decreasing functions of the heat flux q_w (x), the Nusselt number distribution is more uniform. It can be observed for all types of nozzles. Very similar values of the Nusselt number occur especially for the non-uniform heat flux 5000-2500W/m². For constant values of the heat flux q(x) = 5000W/m², the line of the average Nusselt number has a trend to increase slightly in the direction of the flow. Numerical analysis of different mesh density results in good convergence of the GCI index, what excludes mesh size dependency. The presented study is an extension of the paper (Marzec and Kucaba-Piętal, 2016) and aims at answering the question how the Nusselt number distribution on the cooled surface is affected by various geometries of nozzles for a non-uniform surface heat flux q_w (x).

Źródło:

Journal of Theoretical and Applied Mechanics; 2017, 55, 4; 1313-1324
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 53.

Tytuł:

Numerical modelling of bio-heat transfer using the boundary element method
Modelowanie numeryczne przepływu bio-ciepła za pomocą metody elementów brzegowych

Autorzy:

Majchrzak, E.

Powiązania:

https://bibliotekanauki.pl/articles/281250.pdf

Data publikacji:

1998

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

boundary element method
bio-heat transfer
numerical simulation

Opis:

Numerical models of heat transfer processes proceeding in a biological tissue subjected to a strong external thermal interaction are discussed. In this case one can consider diametrically different phenomena; such as burns resulting from thermal contact of the skin with an external heat source, or the freezing process of biological tissue used in cryosurgery. From the mathematical point of view these processes belong to the group of boundary-initial problems described by the diffusion equation and adequate boundary-initial conditions. At the stage of numerical realization the boundary element method can be applied and such an approach is discussed in this paper.
W pracy przedstawiono opisy matematyczne i modele numeryczne procesów cieplnych zachodzących w tkance biologicznej poddanej silnym termicznym oddziaływaniom zewnętrznym. Można tu rozpatrywać skrajnie różne zjawiska, takie jak oparzenia wynikające z kontaktu skóry z zewnętrznym źródłem ciepła, lub też proces zamrażania tkanki w czasie zabiegu kriochirurgicznego. Z matematycznego punktu widzenia procesy te należą do grupy zadań brzegowo-początkowych opisanych równaniami dyfuzji i odpowiednimi warunkami jednoznaczności. Na etapie realizacji numerycznej można wykorzystać metodę elementów brzegowych i takie właśnie podejście jest prezentowane w niniejszej pracy.

Źródło:

Journal of Theoretical and Applied Mechanics; 1998, 2; 437-455
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 54.

Tytuł:

Badania przejmowania ciepła podczas wrzenia na pęku rur ogrzewanych elektrycznie
Investigation of boiling heat transfer in an electrically heated tube bundle

Autorzy:

Krasowski, K.
Cieśliński, J. T.

Powiązania:

https://bibliotekanauki.pl/articles/396908.pdf

Data publikacji:

2010

Wydawca:

ENERGA

Tematy:

wymiana ciepła
badania eksperymentalne
heat transfer
experimental test

Opis:

The paper presents the results of experimental research on water, methanol and R141b refrigerant boiling in a horizontal bundle of smooth tubes supposed to represent part of a flooded evaporator. Experiments were carried out for a bundle of 19 tubes in triangular layout for two spacing-to-diameter ratio values -1.7 and 2.0 - in atmospheric and subatmospheric pressure conditions. Heat transfer coefficient values - both local, tube-specific, and general, for the entire bundle - were determined. The boiling process at the bundle was visualized with a CCD camera and laser sheet technique. A correlation equation allowing the calculation of the average heat transfer coefficient for boiling in smooth tube bundles has been proposed.

Źródło:

Acta Energetica; 2010, 3; 31-40
2300-3022

Pojawia się w:

Acta Energetica

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 55.

Tytuł:

Computer simulation of temperature distribution on a solid target for 201Tl production

Autorzy:

Aboudzadeh Rovais, M. R.
Yousefi, K.
Ardaneh, K.
Mirzaii, M.

Powiązania:

https://bibliotekanauki.pl/articles/147613.pdf

Data publikacji:

2011

Wydawca:

Instytut Chemii i Techniki Jądrowej

Tematy:

heat transfer
computer simulation
solid target
thallium-201

Opis:

Thallium-201 is of great interest in nuclear medicine for diagnostic purposes. It is produced by the 203Tl(p,3n)201Pb nuclear reaction. Since the target for 201Tl production is a solid target and the maximum beam current for the irradiation has a direct relation with its temperature surface, therefore, the control of temperature during the irradiation is essential. Designing a proper cooling system is one of the important and determining parameters in radionuclide production efficiency. Non-controlled temperature would cause melting and consequently loss of target materials that could be very costly especially when an isotopically enriched material is used. In this study, the heat transfer and temperature distribution on the target has been simulated based on a computational fluid dynamics (CDF) code for the thermal behavior of the target during the irradiation and under the different beam currents, cooling flow rates and target designing. The results on the routinely used target for the production of 201Tl in AMIRS, showed that there was a good linearity between proton beam currents (in the range of 100–350 mi A) and maximum temperature on the thallium target (345–458 K). The results also showed that the flow rate of the cooling water can be brought down (from routinely used 45 L/min) to 15 L/min without any risk of melting of target material.

Źródło:

Nukleonika; 2011, 56, 4; 283-289
0029-5922
1508-5791

Pojawia się w:

Nukleonika

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 56.

Tytuł:

MHD flow and heat transfer of a micropolar fluid over a stretchable disk
Przepływ magnetohydrodynamiczny oraz przewodzenie ciepła w cieczy mikropolarnej opływającej rozciągliwy dysk

Autorzy:

Ashraf, M.
Batool, K.

Powiązania:

https://bibliotekanauki.pl/articles/949183.pdf

Data publikacji:

2013

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

magnetohydrodynamics (MHD)
micropolar fluids
heat transfer
stretchable disk

Opis:

A numerical study of an axisymmetric steady laminar incompressible flow of an electrically conducting micropolar fluid over a stretchable disk is carried out when the fluid is subjected to an external transverse magnetic field. The governing nonlinear equations of motion are transformed into a dimensionless form through Von Karman’s logic similarity functions. An algorithm based on a finite difference scheme is used to solve the reduced coupled nonlinear ordinary differential equations with the associated boundary conditions. Effects of the micropolar parameters, the magnetic parameter and the Prandtl number on the flow velocity and temperature distribution are discussed. Investigations predict that the heat transfer rate at the surface of the disk increases with an increase in the values of micropolar parameters. The magnetic field enhances the shear and couple stresses. The shear stress factor is lower for micropolar fluids as compared to Newtonian fluids, which may be beneficial in flow and heat control of polymeric processing.
W pracy zaprezentowano wyniki badań numerycznych nad osiowo-symetrycznym, laminarnym i ustalonym opływem elektrycznie przewodzącej cieczy mikropolarnej wokół rozciągliwego dysku przy jednoczesnym oświetleniu cieczy polem magnetycznym. Nieliniowe równanie ruchu opływu sprowadzono do postaci bezwymiarowej za pomocą funkcji podobieństwa von Karmana. Do rozwiązania uproszczonych, sprzężonych i nieliniowych równań różniczkowych zwyczajnych z towarzyszącymi warunkami brzegowymi użyto algorytmu opartego na metodzie różnic skończonych. Przedyskutowano wpływ parametrów mikropolarności, wartości pola magnetycznego oraz liczby Prandtla na rozkład prędkości i temperatury cieczy. Według badań, tempo przepływu ciepła na powierzchni dysku wzrasta z rosnącymi wartościami parametrów mikropolarności. Dodatkowo, obecność pola magnetycznego powiększa naprężenia ścinające i momentowe. Wartość naprężeń ścinających jest mimo to mniejsza dla cieczy mikropolarnej niż dla newtonowskiej, co może być korzystne w monitorowaniu przepływu i transferu ciepła podczas procesu obróbki polimerów.

Źródło:

Journal of Theoretical and Applied Mechanics; 2013, 51, 1; 25-38
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 57.

Tytuł:

Numerical investigation of pool nucleate boiling in nanofluid with lattice Boltzmann method

Autorzy:

Rostamzadeh, A.
Jafarpur, K.
Rad, E. G.

Powiązania:

https://bibliotekanauki.pl/articles/949317.pdf

Data publikacji:

2016

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

pool boiling
nanofluid
lattice Boltzmann method
heat transfer

Opis:

Due to significant improvement of thermal performance and other properties of nanofluids, this group of liquids is in high demand. According to the literature, the effect of nanoparticles on boiling heat transfer enhancement or degradation is not the same among different investigations. In the present article, the pseudo-potential multiphase lattice Boltzmann method is used to simulate nucleate pool boiling with two different fluids: a pure liquid and a nanofluid. The current results indicate that the contact angle is the same for both the fluid and nanofluid when the vapor bubble detachment occurs. Also, bubble departure diameter is greater in the base liquid while bubble release frequency is higher in the nanofluid. In brief, the present results demonstrate that using a nanofluid instead of its base fluid will increase the boiling heat transfer coefficient.

Źródło:

Journal of Theoretical and Applied Mechanics; 2016, 54, 3; 811-825
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 58.

Tytuł:

Boiling in micro-channels

Autorzy:

Hetsroni, G.

Powiązania:

https://bibliotekanauki.pl/articles/199886.pdf

Data publikacji:

2010

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

micro-channel
boiling
pressure drop
heat transfer
fluctuation

Opis:

Boiling heat transfer in micro-channels is a subject of intense academic and practical interest. Though many heat transfer correlations have been proposed, most were empirically formulated from experimental data. However, hydrodynamic and thermal aspects of boiling in micro-channels are not well understood. Moreover, there are only a few theoretical models that link the heat transfer mechanism with flow regimes in micro-channels. Also, there are discrepancies between different sets of published results, and heat transfer coefficients have either well exceeded, or fallen far below, those predicted for conventional channels. Here we consider these problems with regard to micro-channels with hydraulic diameters ranging roughly from 5 ěm to 500 ěm, to gain a better understanding of the distinct properties of the measurement techniques and uncertainties, the conditions under which the experimental results should be compared to analytical or numerical predictions, boiling phenomenon, as well as different types of micro-channel heat sinks. Two-phase flow maps and heat transfer prediction methods for vaporization in macro-channels are not applicable in micro-channels, because surface tension dominates the phenomena, rather than gravity forces. The models of convection boiling should correlate the frequencies, sizes and velocities of the bubbles and the coalescence processes, which control the flow pattern transitions, together with the heat flux and the mass flux. Therefore, the vapour bubble size distribution must be taken into account. The flow pattern in parallel micro-channels is quite different from that in a single micro-channel. At same values of heat and mass flux, different, time dependent, flow regimes occur in a given micro-channel. At low vapour quality, heat flux causes a sudden release of energy into the vapour bubble, which grows rapidly and occupies the entire channel cross section. The rapid bubble growth pushes the liquid-vapour interface on both caps of the vapour bubble, at the upstream and the downstream ends, and leads to a reverse flow. We term this phenomenon as explosive boiling. One of the limiting operating conditions with flow boiling is the critical heat flux (CHF). The CHF phenomenon is different from that observed in conventional size channels.

Źródło:

Bulletin of the Polish Academy of Sciences. Technical Sciences; 2010, 58, 1; 155-163
0239-7528

Pojawia się w:

Bulletin of the Polish Academy of Sciences. Technical Sciences

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 59.

Tytuł:

Simulation of photovoltaic panel cooling beneath a single nozzle based on a configurations framework

Autorzy:

Mzad, Hocine
Otmani, Abdessalam

Powiązania:

https://bibliotekanauki.pl/articles/1845494.pdf

Data publikacji:

2021

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

photovoltaic panel
nozzle
dispersion
comsol
glazing
heat transfer

Opis:

Solar cell performance decreases with increasing temperature, heat can reduce output efficiency by 10–25%. The operating temperature plays a key role in the photovoltaic conversion process. Increase in electrical efficiency depends on cooling techniques, in particular photovoltaic modules installed in the high temperature regions. A cooling process using a single nozzle of photovoltaic panel operating under different configurations was simulated. The simulation contains two parts: the first is a thermodynamic investigation of fluid impingement upon the sensor front face. The second is a performance comparison between two types of glass cover. The major result that emerges from this simulation is the effect of a single nozzle arrangement to enhance the cooling process, under a low cadence of impinging droplets in the range 0.1–1.7 m/s.

Źródło:

Archives of Thermodynamics; 2021, 42, 1; 115-128
1231-0956
2083-6023

Pojawia się w:

Archives of Thermodynamics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 60.

Tytuł:

Heat transfer in compact cross-flow mini heat exchanger

Autorzy:

Prończuk, Mateusz
Pabiś, Aleksander

Powiązania:

https://bibliotekanauki.pl/articles/27315660.pdf

Data publikacji:

2023

Wydawca:

Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie

Tematy:

heat transfer
cross-flow
mini heat exchanger
optimization based method

Opis:

This paper presents the results of an analysis of heat transfer in a cross-flow mini heat exchanger (CFMHE). The purpose of the paper was to analyze the results of the experimental measurements presented in the previous work in order to determine dimensionless correlations that allow for the calculation of heat transfer coefficients for the CFMHE. Analyzed CFMHE consisted of a brass cylindrical core, in which 2 mm circular holes were drilled. A method based on an optimization procedure was used to determine the correlations describing the heat transfer coefficients, allowing the correlations to be determined without the need of measuring the mini channel wall temperature. Overall heat transfer coefficients calculated using the proposed correlations typically did not deviate by more than ±10% from the corresponding experimental results, which was a significant improvement in the quality of the fit compared to the results presented in previous work.

Źródło:

Polish Journal of Chemical Technology; 2023, 25, 3; 79--88
1509-8117
1899-4741

Pojawia się w:

Polish Journal of Chemical Technology

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 61.

Tytuł:

Heat transfer in combustion chamber of piston engines

Autorzy:

Jankowski, A.

Powiązania:

https://bibliotekanauki.pl/articles/950137.pdf

Data publikacji:

2010

Wydawca:

Instytut Techniczny Wojsk Lotniczych

Tematy:

internal combustion engines
heat transfer
heat flux
combustion chamber
heat losses

Opis:

Measurements were made during downward propagation of a flat flame in a lean limit methane/air mixture. It was observed that the limit flames are very thick and that heat losses to the walls caused extensive cooling of the product gases within 0.05 m behind the propagating flame. Analysis of all data from well synchronized measurements as well as the results of following to them numerical calculations made possible to understand in detail physical picture of heat transfer from the hot gases to the cold walls. It is a unique way for explanation of heat transfer phenomenon. Measurements and calculations were used to prepare heat balance in a flammability tube. In the next step measurements were carried out in a rotating cylindrical combustion chamber. This chamber was treated as a model of piston engine combustion chamber with swirl. Temperature changes on a surface of the rotating combustion chamber were transmitted towards motionless data acquisition system. The temperature measurements were carried out with the use of special thermocouples located at the front wall of the chamber. Influence of rotation velocity on heat transfer was investigated in the range from 1000rpm to 5000 rpm. For a constant mixture concentration maximum temperature rise depended on the rotation velocity. Increased rotation velocity initially intensified heat transfer to the wall, with following to it increase of peak temperature, but further rise of rotation velocity resulted in local flame extinction near the s idę walls, decreased volume of combustion gases, and as a result of these, decreased value of peak temperature at the wall surface. Presented techniques make possible estimate heat losses to the walls in a combustion chamber of piston engines.

Źródło:

Journal of KONES; 2010, 17, 1; 187-197
1231-4005
2354-0133

Pojawia się w:

Journal of KONES

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 62.

Tytuł:

Analyses of heat transfer through walls of thermal technical spaces with computer helping

Autorzy:

Janczarek, M. M.

Powiązania:

https://bibliotekanauki.pl/articles/117968.pdf

Data publikacji:

2014

Wydawca:

Polskie Towarzystwo Promocji Wiedzy

Tematy:

heat transfer
technical storages
physical modeling
control process

Opis:

The paper describes research work on methods concerning heat transfers through walls of thermal technical chambers. This paper is focused on the new concept of thermal analysis derived from harmonic character of temperature changes in building environment with aspect on conductive heat transfers through walls.. The paper presents exemplary measurement results taken in Lublin region during various periods throughout a year. The purpose for the research is to point out areas subjected to the highest energy losses caused by building’s construction and geographical orientation of walls in the aspect of daily atmospheric temperature changes emerging on chamber exterior.

Źródło:

Applied Computer Science; 2014, 10, 4; 75-83
1895-3735

Pojawia się w:

Applied Computer Science

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 63.

Tytuł:

Non-stationary heat transfer in a hollow cylinder with functionally graded material properties
Niestacjonarny przepływ ciepła w wydrążonym cylindrze wykonanym z materiału o funkcyjnej gradacji własności

Autorzy:

Ostrowski, P.
Michalak, B.

Powiązania:

https://bibliotekanauki.pl/articles/281045.pdf

Data publikacji:

2011

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

heat transfer
functionally graded material
tolerance averaging approach

Opis:

The unidirectional non-stationary heat conduction in a two-phase hollow cylinder is considered. The conductor is made of two-phase stratified composites and has smooth gradation of effective properties in the radial direction. Therefore, we deal here with a special case of functionally graded materials, FGM. The formulation of mathematical model of the conductor is based on a tolerance averaging approach (TAA). Application to the non-stationary heat conduction and a comparison of the tolerance model with the asymptotic one is shown. The effect of geometry and material properties of the conductor on the temperature field is examined.
W pracy rozważano niestacjonarne przewodzenia ciepła w dwuskładnikowym wydrążonym cylindrze. Przewodnik jest wykonany z dwuskładnikowego warstwowego kompozytu mającego łagodną zmienność efektywnych własności w kierunku promieniowym. Stąd mamy tutaj do czynienia ze specjalnym przypadkiem materiału o funkcyjnej gradacji własności (ang. functionally graded materiale, FGM). Zbudowanie uśrednionego modelu matematycznego rozpatrywanego przewodnika jest oparte na technice tolerancyjnej aproksymacji. W pracy pokazano zastosowanie otrzymanego modelu tolerancyjnego i porównanie wyników z wynikami dla modelu asymptotycznego w przypadku niestacjonarnego przewodzenia ciepła. Zbadano wpływ zmienności geometrii i własności materiałowych przewodnika na pole tempertatury.

Źródło:

Journal of Theoretical and Applied Mechanics; 2011, 49, 2; 385-397
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 64.

Tytuł:

The heat transfer coefficient calculation in the ice cylinder based on in-cylinder pressure data

Autorzy:

Przybyła, G.
Postrzednik, S.
Żmudka, Z.

Powiązania:

https://bibliotekanauki.pl/articles/247975.pdf

Data publikacji:

2013

Wydawca:

Instytut Techniczny Wojsk Lotniczych

Tematy:

heat transfer coefficient
combustion engines
in-cylinder pressure

Opis:

In this paper the calculations algorithm of heat-transfer coefficient in the combustion chamber of the internal combustion engine is presented. Developed algorithm is based on the in cylinder pressure data. The proposed algorithm can be helpful to determine the average values of heat-transfer coefficient from working medium to the combustion chamber walls (crown of a cylinder head, cylinder walls and piston head) during combustion process. The calculation method includes modified one zone heat release model in combustion chamber of SI engine. Proposed method consists in closing the energy balance equation by the coefficient which expresses the heat losses to the walls of the combustion chamber. The average value of the heat losses during combustion process is calculated by two steps. Firstly, the integration of the energy balance equation (without specifying the heat losses) leads to designation of the so-called net value of heat released in cylinder. In the next step the amount of the total energy supplied to the cylinder is determined taking into account the chemical energy of the supplied fuel. The difference between the supplied value of chemical energy and heat released net value allows to determine the heat losses average value. In last stage, the heat flow equation leads to calculate the mean value of heat transfer coefficient during combustion process.

Źródło:

Journal of KONES; 2013, 20, 4; 382-388
1231-4005
2354-0133

Pojawia się w:

Journal of KONES

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 65.

Tytuł:

Numerical analysis of a heat transfer in economizer dedicated for 250 KW power solid fuel heating boiler

Autorzy:

Judt, W.
Bartoszewicz, J.

Powiązania:

https://bibliotekanauki.pl/articles/243437.pdf

Data publikacji:

2018

Wydawca:

Instytut Techniczny Wojsk Lotniczych

Tematy:

heating boiler
heat transfer
economizer
fluent
solid fuel

Opis:

Heating boilers, which are combusting solid fuels, are a very popular heating device in Poland. Heating boilers for solid fuels with nominal power equal to 250-300 kW reach a high level of waste heat. Polish companies produced a significant amount of heating boilers with that level of heating power, which are being exploited all the time in smaller companies and housing associations. A temperature of exhaust gases in the outlet of the heating boiler can be equal to 270-300ºC. It means that it is possible to recover some part of the waste heat. It can be realizable in an external heat exchanger. The article contains a methodology of a heat transfer process calculation for this type of heat exchangers. Estimated waste heat, which can be recovered from this installation, is equal to 25 kW. Additional heat exchanger implementation into a plant can increase an efficiency of solid fuel combustion process for a 10 percent. Construction of a heat exchanger was calculated during analytical calculations. After that, analytical calculations were verified in numerical calculations. Numerical analysis of a heat exchanger model was realized in the ANSYS Fluent environment. During calculations, a shell-and-tube heat exchanger construction was analysed. Authors of the article analysed a real temperature distribution for exhaust gases located on a shell side and for a water, which are located on a tube side of the economizer. Numerical calculations allowed to model conditions of economizer steady state work for a whole volume of this construction.

Źródło:

Journal of KONES; 2018, 25, 2; 164-168
1231-4005
2354-0133

Pojawia się w:

Journal of KONES

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 66.

Tytuł:

Thermal state simulation for cylinder of marine two stroke engine

Autorzy:

Kowalski, J.

Powiązania:

https://bibliotekanauki.pl/articles/244344.pdf

Data publikacji:

2007

Wydawca:

Instytut Techniczny Wojsk Lotniczych

Tematy:

marine two-stroke engines
modelling
radiosity
heat transfer

Opis:

This paper deals with the modelling of heat flow through cylinder liner structural components of a two-stroke engine. Especially, I paid attention to simulating temperature distribution for the wet cylinder liner. Multidimensional equations for the transient heat conduction with the Dirichlet and Fourier boundary conditions have been applied. In particularly, local values for the convective and radiative heat transfer coefficients using the Fourier boundary conditions determined in space of cylinder volume are applied. In order to determine the temperature distribution for the considered space, the radiosity method is used. Simulation results have been presented in the form of a temperature field for cylinder liner structural components depending on the crankshaft position angle. Application of the iterative calculation method for solving differential equations of energy balance allowed me to use software easy to get. I carried out all iterative computations using MSEXCEL spreadsheet. This way, I could decrease the simulation cost significantly. The simplicity of such an approach allowed me to apply the obtained results for visualization of the conduction heat transfer phenomena occurring in a cylinder of working marine engine. The presented approach could be used for the development of ship machinery simulators as well.

Źródło:

Journal of KONES; 2007, 14, 4; 209-216
1231-4005
2354-0133

Pojawia się w:

Journal of KONES

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 67.

Tytuł:

Calculation method for flow boiling and flow condensation of R134a and R1234yf in conventional and small diameter channels

Autorzy:

Mikielewicz, D.
Jakubowska, B.

Powiązania:

https://bibliotekanauki.pl/articles/259535.pdf

Data publikacji:

2017

Wydawca:

Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa

Tematy:

heat transfer coefficient
flow boiling
conventional channels
minichannels

Opis:

The paper presents the results of calculations performed using the authors’ model to predict the heat transfer coefficient during flow boiling for two refrigerants R134a and R1234yf. The experimental data from various past studies have been collected and the calculations have been conducted for the full range of quality variation and a wide range of mass velocity. The aim of the study was to test the sensitivity of the in-house flow boiling and flow condensation model. The importance of taking into account the surface tension as the parameter exhibiting its importance in case of the flow in minichannels, as well as the influence of the reduced pressure were analysed. The obtained numerical results show good consistency with those recorded in the experiments.

Źródło:

Polish Maritime Research; 2017, S 1; 141-148
1233-2585

Pojawia się w:

Polish Maritime Research

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 68.

Tytuł:

Heat Conduction Analysis of a Hollow Sphere made of Three Different Layers of Materials

Autorzy:

Khan, S. M. Khaled
Islam, Md. Mashrur

Powiązania:

https://bibliotekanauki.pl/articles/1062861.pdf

Data publikacji:

2019

Wydawca:

Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN

Tematy:

Heat transfer
Material Science
Naiver-Strokes
Spherical Contour

Opis:

A systematic arrangement has been gotten for the transient issue of three-dimensional multilayer heat conduction in a circle with layers in the spiral course. The arrangement strategy can be connected to an empty circle or a strong circle made out of a few layers of different materials. By and large, the partition of factors connected to 3D round directions has interesting attributes because of the nearness of related Legendre works as the eigenfunctions. Additionally, an eigenvalue issues the azimuthal way likewise requires arrangement; once more, its properties are one of a kind inferable from periodicity the azimuthal way. In this way, broadening existing arrangements in 2D round directions to 3D circular directions isn't clear. In a round facilitate framework, one can explain a 3D transient multilayer heat conduction issue without the nearness of fanciful eigenvalues. A 2D tube shaped polar facilitate framework is the main other case in which such multidimensional issues can be tackled without the utilization of nonexistent eigenvalues. The nonappearance of nonexistent eigenvalues renders the arrangement philosophy fundamentally increasingly valuable for pragmatic applications. The strategy portrayed can be utilized for all the three kinds of limit conditions in the external and inward surfaces of the circle. The arrangement method is shown on an illustrative issue for which results are gotten.

Źródło:

World Scientific News; 2019, 127, 3; 248-259
2392-2192

Pojawia się w:

World Scientific News

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 69.

Tytuł:

Parallelized numerical code for derivation of heat transfer coefficient from experimental data

Autorzy:

Telega, J.
Doerffer, P.
Szwaba, R.
Kaczyński, P.

Powiązania:

https://bibliotekanauki.pl/articles/1938631.pdf

Data publikacji:

2015

Wydawca:

Politechnika Gdańska

Tematy:

Matlab parallel computation
heat transfer coefficient
blade cooling

Opis:

An application of parallel computation capabilities in the MATLAB language for the analysis of experimental data concerning the heat transfer coefficient on ribbed walls is presented in this paper. A description of the experimental study, mathematical model and numerical implementation is also given. The obtained results of measurements and calculations shown here clearly indicate the influence of ribbed walls on the heat transfer coefficient distribution in an internal, subsonic flow.

Źródło:

TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2015, 19, 2; 197-205
1428-6394

Pojawia się w:

TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 70.

Tytuł:

Dry and Wet Heat Transfer Through Clothing Dependent on the Clothing Properties Under Cold Conditions

Autorzy:

Richards, M. G. M.
Rossi, R.
Meinander, H.
Broede, P.
Candas, V.
Hartog den, E.
Holmer, I.
Nocker, W.
Havenith, G.

Powiązania:

https://bibliotekanauki.pl/articles/90562.pdf

Data publikacji:

2008

Wydawca:

Centralny Instytut Ochrony Pracy

Tematy:

heat transfer
moisture
condensation
wet conduction
clothing systems

Opis:

The purpose of this study was to investigate the effect of moisture on the heat transfer through clothing in relation to the water vapour resistance, type of underwear, location of the moisture and climate. This forms part of the work performed for work package 2 of the European Union THERMPROTECT project. Thermal manikin results of dry and wet heat loss are presented from different laboratories for a range of 2-layer clothing with similar dry insulations but different water vapour permeabilities and absorptive properties. The results obtained from the different manikins are generally consistent with one another. For each climate, total wet heat loss is predominately dependent on the permeability of the outer layer. At 10 °C, the apparent evaporative heat loss is markedly higher than expected from evaporation alone (measured at 34 °C), which is attributed to condensation within the clothing and to increased conductivity of the wet clothing layers.

Źródło:

International Journal of Occupational Safety and Ergonomics; 2008, 14, 1; 69-76
1080-3548

Pojawia się w:

International Journal of Occupational Safety and Ergonomics

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

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Skocz do pozycji: 71.

Tytuł:

Heat transfer processes in installations with photovoltaic roof tiles

Autorzy:

Kurz, D.

Powiązania:

https://bibliotekanauki.pl/articles/97640.pdf

Data publikacji:

2016

Wydawca:

Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej

Tematy:

photovoltaic roof tile
convection
radiation
conduction
heat transfer

Opis:

The paper presents the classification of methods of heat transfer, and the procedure when determining criterion equations depending on the type of heat exchange. It describes the heat transfer coefficients and resistance of heat transfer by convection. It also indicates the workflow to determine the quantitative heat flow in the present system of photovoltaic roof tiles installed in the roof structure.

Źródło:

Computer Applications in Electrical Engineering; 2016, 14; 444-456
1508-4248

Pojawia się w:

Computer Applications in Electrical Engineering

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 72.

Tytuł:

Hall effects on MHD flow past an accelerated plate with heat transfer

Autorzy:

Sundarnath, J. K.
Muthucumarswamy, R.

Powiązania:

https://bibliotekanauki.pl/articles/264878.pdf

Data publikacji:

2015

Wydawca:

Uniwersytet Zielonogórski. Oficyna Wydawnicza

Tematy:

Hall parameter
Hartmann number
heat transfer
Prandtl number

Opis:

Hall current and rotation on an MHD flow past an accelerated horizontal plate relative to a rotating fluid, In the presence of heat transfer has been analyzed. The effects of the Hall parameter, Hartmann number, rotation parameter (non-dimensional angular velocity), Grashof’s number and Prandtl number on axial and transverse velocity profiles are presented graphically. It is found that with the increase in the Hartmann number, the axial and transverse velocity components increase in a direction opposite to that of obtained by increasing the Hall parameter and rotation parameter. Also, when […], it is observed that the transverse velocity component vanishes and axial velocity attains a maximum value.

Źródło:

International Journal of Applied Mechanics and Engineering; 2015, 20, 1; 171-181
1734-4492
2353-9003

Pojawia się w:

International Journal of Applied Mechanics and Engineering

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

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Skocz do pozycji: 73.

Tytuł:

Identification of the Heat Transfer Coefficient at the Charge Surface Heated on the Chamber Furnace

Autorzy:

Gołdasz, A.
Malinowski, Z.

Powiązania:

https://bibliotekanauki.pl/articles/356595.pdf

Data publikacji:

2017

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

heat transfer coefficient
inverse method
finite element method

Opis:

The inverse method was applied to determine the heat flux reaching the charge surface. The inverse solution was based upon finding the minimum of the error norm between the measured and calculated temperatures. The charge temperature field was calculated with the finite element method by solving the heat transfer equation for a square charge made of 15HM steel heated on all its surfaces. On the basis of the mean value of heat flux, the value of the heat transfer coefficient at each surface was determined depending on the surface temperature of the material heated.

Źródło:

Archives of Metallurgy and Materials; 2017, 62, 2A; 509-513
1733-3490

Pojawia się w:

Archives of Metallurgy and Materials

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

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Skocz do pozycji: 74.

Tytuł:

The Influence of the Model Selected Parameter Measurement Error on the Accuracy of Heat Transfer Coefficient Determination Method for Contact between Rolls and the Cast Strand

Autorzy:

Rywotycki, M.

Powiązania:

https://bibliotekanauki.pl/articles/353068.pdf

Data publikacji:

2016

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

heat transfer
inverse solution
solid to solid interface

Opis:

The paper presents a heat transfer model between two surfaces which are in contact under an external force. The developed heat transfer boundary condition model has been obtained using a new methodology for determining heat flux transferred between two solid surfaces. The methodology consists of two parts: experimental and numerical one. The experimental part involves measurements of temperature at specific points in two samples brought into contact. The numerical part uses an inverse method and the finite element method to calculate the heat flux at the interface.

Źródło:

Archives of Metallurgy and Materials; 2016, 61, 4; 2061-2070
1733-3490

Pojawia się w:

Archives of Metallurgy and Materials

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

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Skocz do pozycji: 75.

Tytuł:

Thermal Modelling for Production of Hot Strip of Magnesium Alloy

Autorzy:

Nam, A.
Prufert, U.
Kawalla, R.

Powiązania:

https://bibliotekanauki.pl/articles/99479.pdf

Data publikacji:

2014

Wydawca:

Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych

Tematy:

magnesium coil heating
nonlinear heat transfer
numerical simulation

Opis:

The paper deals with a thermal modelling of a magnesium coil in the magnesium strip production. The magnesium coil heating is the preparation step for the magnesium hot strip rolling and occurs in the special air circulating furnace. The cooling of the coil takes place on the several steps such as a transport of coil after heating from the furnace to a mill coiler. The aim of the work is to develop a tool to accurately simulate the temperature distribution within coil during the magnesium coil heating in the furnace. The major thermal properties for material and furnace were determined indirectly based on experimental data. Simulation results are compared to data obtained from experimental trials.

Źródło:

Journal of Machine Engineering; 2014, 14, 1; 29-38
1895-7595
2391-8071

Pojawia się w:

Journal of Machine Engineering

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 76.

Tytuł:

Heat transfer coefficient measurements on curved surfaces

Autorzy:

Kurowski, Marcin

Powiązania:

https://bibliotekanauki.pl/articles/1845471.pdf

Data publikacji:

2021

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

heat transfer coefficient
measurements
methodology
gas turbine
cooling

Opis:

This paper presents the results of experimental research on heat transfer distribution under the impinging jets at high jet velocity on curved surfaces. The air jets flow out from the common pipe and impinge on a surface which is cooled by them, in this way all together create a model of external cooling system of low pressure gas turbine casing. Preliminary measurement results from the flat plate case were compared with the results from the curved surface case. Surface modification presented in this paper relied on geometry change of flat surface to the form of a ‘bump’. The special system of pivoted mirrors was implemented during the measurements to capture the heat exchange on curved surfaces of the bump. The higher values of mean heat transfer coefficient were observed for all flow cases with a bump in relation to the reference flow case with a flat plate.

Źródło:

Archives of Thermodynamics; 2021, 42, 2; 155-170
1231-0956
2083-6023

Pojawia się w:

Archives of Thermodynamics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 77.

Tytuł:

The Heat Transfer Process Between Two Bodies with a Large Temperature Difference

Autorzy:

Przyłucka-Bednarska, Aleksandra
Rywotycki, Marcin
Sołek, Krzysztof
Malinowski, Zbigniew

Powiązania:

https://bibliotekanauki.pl/articles/2134108.pdf

Data publikacji:

2022

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

heat transfer coefficient
thermal conductivity
inverse solution
steel

Opis:

Heat transport when two surfaces of solids come into contact is an important phenomenon in many metallurgical processes. Determining the boundary conditions of heat transfer allows to obtain the correct solutions of the heat conduction equation. The paper presents models for determining the heat transfer coefficient between steel materials in contact. Experimental tests were carried out to measure the temperature changes of the contacting samples made of steel S235 (1.0038) and steel 15HM (1.7335) under the pressure of 10, 15 and 20 MPa. There was a large temperature difference between the samples. The results of the experiment were compared with numerically calculated temperatures and the value of the heat transfer coefficient was determined at different pressure values depending on the time.

Źródło:

Archives of Metallurgy and Materials; 2022, 67, 3; 1161--1165
1733-3490

Pojawia się w:

Archives of Metallurgy and Materials

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 78.

Tytuł:

Heat Transfer Characteristics of a Combination of Two Double-chamber Windows

Autorzy:

Basok, Borys
Davydenko, Borys
Pavlenko, Anatoliy
Novikov, Volodymyr
Goncharuk, Svitlana

Powiązania:

https://bibliotekanauki.pl/articles/27322950.pdf

Data publikacji:

2023

Wydawca:

Politechnika Koszalińska. Wydawnictwo Uczelniane

Tematy:

heat loss
double-chamber windows
numerical modelling
heat transfer resistance

Opis:

Low-emissivity coatings on glass surfaces, inert gas instead of air between glasses, and double-glazed windows are usually used to reduce heat loss from a room through windows. This effect can also be achieved by installing two double-chamber windows in one window opening at a certain distance from each other. This work uses numerical modelling to study the characteristics of heat transfer through a system of two two-chamber windows. The distributions of temperature and airflow velocity due to natural convection in the chambers of double-chamber windows and the space between the windows are analyzed. The distributions of temperatures and heat fluxes over the surfaces of windows are determined depending on the distance between the windows. The dependences on the distance between the windows of radiation, convective, and total heat flow through a system of two double-chamber windows are studied. It is shown that two double-chamber windows located at a certain distance from each other make it possible to increase the heat transfer resistance compared to one two-chamber window without a low-emission coating by 2.6...2.8 times. As the distance between windows increases, a given system's overall heat transfer resistance increases. However, this increase becomes insignificant if this distance is greater than 80 mm.

Źródło:

Rocznik Ochrona Środowiska; 2023, 25; 289--300
1506-218X

Pojawia się w:

Rocznik Ochrona Środowiska

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 79.

Tytuł:

Analiz i modelirovanie teploobmennykh ustrojjstv v kontaktnykh apparatakh
Analysis and simulation of heat exchange devices in the contact devices

Autorzy:

Spinov, V.

Powiązania:

https://bibliotekanauki.pl/articles/77965.pdf

Data publikacji:

2014

Wydawca:

Komisja Motoryzacji i Energetyki Rolnictwa

Tematy:

heat exchange
contact
mass transfer
heat transfer
contact device
energy efficiency
mathematical model

Źródło:

Motrol. Motoryzacja i Energetyka Rolnictwa; 2014, 16, 5
1730-8658

Pojawia się w:

Motrol. Motoryzacja i Energetyka Rolnictwa

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 80.

Tytuł:

Memorandum of prof. A. K. Oppenheim and an example of application of the Oppenheim correlation (OPC)* for the heat losses during the combustion in IC-engine

Autorzy:

Jankowski, A.
Czerwinski, J.

Powiązania:

https://bibliotekanauki.pl/articles/246928.pdf

Data publikacji:

2010

Wydawca:

Instytut Techniczny Wojsk Lotniczych

Tematy:

combustion engines
Oppenheim Correlation OCP
heat transfer
heat looses
Vibe-Function

Opis:

The Oppenheim Correlation (OPC) is an empirical algorithm, which allows a simple estimate of heat losses to the wall during the combustion in IC-engine. In present paper the results ofdifferent applications of OPC will be shown. Even if there are still several needs and ideas for further research it can be stated, that the OPC is a promising possibility of modelling the wali heat losses and due to its simplicity it has to be recommended to the engine community. The OPC can be used not only for didactics purposes, but also for quick simulation of wall heat losses and eventuałły for the on-line regulation of the cooling system. In particular basic milestones of calculation of the working cycle, modelling of heat losses according to Oppenheim (OPC), engines and test procedure, examples of the OPC-application are presented in the paper. The OPC can be recommended to the engine community as a good alternative of modelling and calculation of the heat losses trough the combustion chamber wall.

Źródło:

Journal of KONES; 2010, 17, 2; 181-194
1231-4005
2354-0133

Pojawia się w:

Journal of KONES

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 81.

Tytuł:

Effect of Pressure on the Crystallisation of AlSi7Mg Alloy

Autorzy:

Pastirčák, R.
Ščury, J.

Powiązania:

https://bibliotekanauki.pl/articles/355560.pdf

Data publikacji:

2017

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

squeeze casting
heat transfer coefficient
heat flux
Al alloys
mechanical properties

Opis:

This paper deals with influencing the crystallisation of Al alloys by a direct squeeze casting method. The effects of changed cooling rates of the casting is evaluated using a heat transfer coefficient at different casting conditions. The experimental results obtained by temperature measurement of the casting and the mould were used to predict the casting and mould surface temperatures using regression curves. The measured temperatures in the sub-surface layers were used to determine the amount of heat transferred from the casting to the mould. The amount of transferred heat increased 20-fold due to the effect of pressure. We also evaluated the effect of the acting pressure on the mechanical properties and microstructure of the alloy used. The process parameters were varied in the experiment.

Źródło:

Archives of Metallurgy and Materials; 2017, 62, 4; 2193-2198
1733-3490

Pojawia się w:

Archives of Metallurgy and Materials

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 82.

Tytuł:

Numerical modelling and analysis of cooling system of electrical transformer dipped into polymerised resin

Autorzy:

Smołka, J.
Nowak, A. J.
Wrobel, L. C.

Powiązania:

https://bibliotekanauki.pl/articles/1955729.pdf

Data publikacji:

2003

Wydawca:

Politechnika Gdańska

Tematy:

dry electrical transformer
heat transfer
natural convection
coupled analysis

Opis:

This paper discusses a numerical model of the heat dissipation processes in an electrical transformer dipped into polymerised resin. The transformer is cooled by both natural convection (via the ambient air) and forced convection (via the water cooling system attached to one of the transformer casing walls). Two cases have been compared, i.e. the cooler connected to the bottom or the top wall of the transformer container, respectively. In order to improve the modelling of the natural convection problem, an independent geometrical model of the surrounding air was created and considered separately. The continuity of temperature and heat flux along the interface between the transformer and air was enforced by an iterative procedure. This procedure allowed one to calculate and then prescribe local heat fluxes to the external walls of the transformer. The numerical results obtained in this project have yielded information on the efficiency of the analysed cooling system.

Źródło:

TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2003, 7, 3; 439-448
1428-6394

Pojawia się w:

TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 83.

Tytuł:

Effects of heat transfer on unsteady magnetohydrodynamics (MHD) boundary layer flow of an incompressible fluid a moving vertical plate

Autorzy:

Falodun, B. O.
Fadugba, S. E.

Powiązania:

https://bibliotekanauki.pl/articles/1178267.pdf

Data publikacji:

2017

Wydawca:

Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN

Tematy:

Boundary layer
Heat transfer
MHD
Thermal radiation
Viscous dissipation

Opis:

This paper deals with the effects of heat transfer on unsteady MHD boundary layer flow of a chemically reading fluid past a vertical plate in the presence of thermal radiation and viscous dissipation. The governing equations of the problem under investigation are systems of partial differential equations. These equations are namely: continuity equation, linear momentum equation and energy equation. These systems of equations were non-dimentionalized by introducing non-dimensional variables. We resulted to dimensionless systems of partial differential equations. The fluid considered in this paper are optically thick, however we employ the Roseland model. Simulations were done numerically on all controlling parameters and the results generated were displayed in graphs and tables. Results review that thermal Grashof number intensifies the velocity profile and increase in Prandtl number leads to decrease in both the velocity and temperature field. Increasing thermal radiation intensifies the velocity and temperature profile. Thermal radiation speeds up the convection flow and thermal boundary layer of the fluid. Increase in magnetic parameter reduces the velocity profile as a result of the applied transverse magnetic field.

Źródło:

World Scientific News; 2017, 88, 2; 118-137
2392-2192

Pojawia się w:

World Scientific News

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 84.

Tytuł:

Computer Aided Thermal Processes In Technical Spaces

Autorzy:

Janczarek, M.
Bulyandra, O.

Powiązania:

https://bibliotekanauki.pl/articles/117689.pdf

Data publikacji:

2017

Wydawca:

Polskie Towarzystwo Promocji Wiedzy

Tematy:

heat transfer
thermal technical chambers
physical modeling
control process

Opis:

This paper describes research work on methods concerning heat transfers through walls of thermal technical chambers. The paper presents the mathematical and physical analysis of problems in the field of energy savings and material selection in thermal chambers in controlled gaseous environment. The purpose for the research is to point out areas subjected to the highest energy losses caused by building’s construction and geo-graphical orientation of walls in the aspect of daily atmospheric temperature changes emerging on chamber exterior. Thermal problems were solved using computer aided support. The paper presents exemplary measurement results taken in Lublin region during various periods throughout a year.

Źródło:

Applied Computer Science; 2017, 13, 2; 82-93
1895-3735

Pojawia się w:

Applied Computer Science

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 85.

Tytuł:

Interval boundary element method for transient diffusion problem in two-layered domain
Przedziałowa metoda elementów brzegowych dla zadań dyfuzji w obszarach dwuwarstwowych

Autorzy:

Piasecka-Belkhayat, A.

Powiązania:

https://bibliotekanauki.pl/articles/280879.pdf

Data publikacji:

2011

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

directed interval arithmetic
interval boundary element method
heat transfer

Opis:

In the paper, the description of an unsteady heat transfer for one- dimensional problem proceeding in a two-layered domain is presented. It is assumed that all thermophysical parameters appearing in the mathematical description of the problem analysed are given as directed interval values. The problem discussed has been solved using the 1st scheme of the interval boundary element method. The interval Gauss elimination method has been applied to solve the obtained interval system of equations. In the final part of the paper, results of numerical computations are shown.
W pracy przedstawiono opis nieustalonego przepływu ciepła dla zadań jednowymiarowych w obszarach dwuwarstwowych. Założono, że wszystkie parametry termofizyczne pojawiające się w opisie matematycznym analizowanego zadania są wartościami przedziałowymi skierowanymi. Omawiane zagadnienie zostało rozwiązane za pomocą pierwszego schematu przedziałowej metody elementów brzegowych. Do rozwiązania otrzymanego interwałowego układu równań zastosowano przedziałową metodę eliminacji Gaussa. W końcowej części pracy pokazano wyniki obliczeń numerycznych.

Źródło:

Journal of Theoretical and Applied Mechanics; 2011, 49, 1; 265-276
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 86.

Tytuł:

Numerical analysis of the effects of changeable transverse and longitudinal pitches and porous media inserts on heat transfer from an elliptic tube bundle

Autorzy:

Razzaghi, H.
Layeghi, M.
Goodarzi, S.
Lotfizadeh, H.

Powiązania:

https://bibliotekanauki.pl/articles/281191.pdf

Data publikacji:

2014

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

elliptic tube bundle
heat transfer
pitches
aluminum foam
efficiency

Opis:

In this paper, effects of changeable transverse and longitudinal pitches and porous media inserts on overall heat transfer from an elliptic tube bundle are studied numerically. Go- verning equations used for the analysis of fluid flow inside the porous media inserts are Darcy-Brinkman-Forchheimer equations, and for the fluid flow without porous inserts are classical Navier-Stokes equations. A finite volume code is used to solve the governing equ- ations. The tube bundle consists of 10 rows of elliptical tubes 3.17 cm in major diameter and 1.4 cm in minor diameter in a staggered arrangement. Aluminum foams are used as porous media inserts between the tubes with three different porosities. It is shown that the use of the aluminum foam enhances heat transfer significantly (more than 50% in some cases). However, the pressure drop increases as the Reynolds number grows. The differences among various cases are also discussed. Finally, it is shown that the overall heat transfer efficiency increases more effectively by increasing the transverse pitch with respect to the longitudinal and diagonal pitches while the flow regime remains laminar.

Źródło:

Journal of Theoretical and Applied Mechanics; 2014, 52, 3; 767-780
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 87.

Tytuł:

Numerical simulation of thermal processes proceeding in a multi-layered film subjected to ultrafast laser heating
Symulacja numeryczna procesów cieplnych zachodzących w wielowarstwowych mikroobszarach poddanych działaniu ultrakrótkiego impulsu laserowego

Autorzy:

Majchrzak, E.
Mochnacki, B.
Suchy, J. S.

Powiązania:

https://bibliotekanauki.pl/articles/281751.pdf

Data publikacji:

2009

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

microscale heat transfer
thin films
laser pulse
numerical modelling

Opis:

In the paper, the mathematical model, numerical algorithm and examples of computations concerning thermal processes proceeding in a multi-layered thin film subjected to an ultrafast laser pulse are discussed. The equations describing a course of the analysed process correspond to the dual-phase-lag model and contain both the relaxation time tau q and additionally the thermalization time tau T. At the stage of numerical simulation, the finite difference method has been used. The algorithm is based on an artificial decomposition of the domain considered, while common thermal interactions between successive layers are taken into account using conditions of heat flux and temperature continuity at points corresponding to internal boundaries (1D task has been considered).
W pracy przedstawiono model matematyczny, algorytm numeryczny i przykłady symulacji dotyczących przebiegu procesów cieplnych w wielowarstwowym mikroobszarze nagrzewanym ultraszybkim impulsem generowanym przez laser. Równanie opisujące przebieg procesu odpowiada modelowi z dwoma opóźnieniami wynikającymi z czasu relaksacji i czasu termalizacji. Na etapie obliczeń numerycznych wykorzystano metodę różnic skończonych. Algorytm bazuje na sztucznej dekompozycji obszaru wielowarstwowego, przy czym wzajemne oddziaływania między warstwami uwzględniono poprzez założenie ciągłości strumienia ciepła i pola temperatury na powierzchniach kontaktu. Biorąc pod uwagę geometrię obszaru, rozpatrywano zadanie jednowymiarowe.

Źródło:

Journal of Theoretical and Applied Mechanics; 2009, 47, 2; 383-396
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 88.

Tytuł:

Measurement approach of mean heat transfer coefficient for packed bed of vegetables

Autorzy:

Łapiński, A.
Butrymowicz, D.
Kołodziejczyk, M.

Powiązania:

https://bibliotekanauki.pl/articles/386873.pdf

Data publikacji:

2017

Wydawca:

Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej

Tematy:

heat transfer coefficient
packed bed
carrot
single blow technique

Opis:

The non-invasive measurement approach of the mean heat transfer coefficient for the packed bed of vegetables may be thought as still open issue. There is a clear need for the assessment of heat transfer conditions for various types of fruits and vegetables in order to accurately predict the thermal load that is necessary to select refrigeration equipment for cold storage chamber. Additionally, there is significant development in numerical modelling of heat and mass transfer processes in cold storage chambers for fruits and vegetables which requires precise heat transfer prediction. The theoretical basis for the indirect measurement approach of mean heat transfer coefficient for the packed bed of vegetables that is based on single blow technique is presented and discussed in the paper. The approach based on the modified model of Liang and Yang was presented and discussed. The testing stand consisted of a dedicated experimental tunnel along with auxiliary equipment and measurement system are presented. The geometry of the tested vegetables bed were presented. Selected experimental results of heat transfer are presented and discussed for the packed bed of carrots. These results were presented as dimensionless relationship. The obtained results were compared with the existing dimensionless relationships developed for the packed bed consisting of elements of various regular shapes.

Źródło:

Acta Mechanica et Automatica; 2017, 11, 1; 73-80
1898-4088
2300-5319

Pojawia się w:

Acta Mechanica et Automatica

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 89.

Tytuł:

Numerical investigations of the engine cooling system in a small power vessel pod propulsion system

Autorzy:

Dymarski, C.
Leśniewski, W.

Powiązania:

https://bibliotekanauki.pl/articles/258590.pdf

Data publikacji:

2008

Wydawca:

Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa

Tematy:

azimuthing electric propulsion
pod propeller
heat transfer
cooling system

Opis:

The development of electronics and electrotechnology enabled to put electric motors of the alternating current in the pod and to use them for the main drive of ships. A lot of heat which must be picked up from the system is a problem which is turning up at applying the system of this type. Many big ships lately contended with these problems. Building the small propeller for the boat powered with solar power we decided to check the influence of the chilling middle on the temperature of the work of an engine. In the article we are presenting a built propeller and a way, into which an issue of the exchange of the heat was analysed using the Fluent software.

Źródło:

Polish Maritime Research; 2008, 4; 59-65
1233-2585

Pojawia się w:

Polish Maritime Research

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 90.

Tytuł:

Charakterystyka pracy krzyżowo-prądowego mikrowymiennika ciepła
Operational characteristics of the crossflow heat exchanger

Autorzy:

Pabiś, A.

Powiązania:

https://bibliotekanauki.pl/articles/1220185.pdf

Data publikacji:

2011

Wydawca:

Stowarzyszenie Inżynierów i Techników Przemysłu Chemicznego. Zakład Wydawniczy CHEMPRESS-SITPChem

Tematy:

mikrowymiennik
wymiana ciepła
współczynnik przenikania ciepła
heat transfer coefficient

Opis:

W artykule przedstawiono wyniki badań pracy prototypowego mikrowymiennika ciepła w układzie woda-woda. Dla zmieniających się natężeń wody ogrzewanej i chłodzonej oraz dla różnych temperatur początkowych gorącej wody, określano strumienie wymienianego ciepła, współczynniki przenikania ciepła oraz opory przepływu mediów przez wymiennik.
Streszczenie angielskie: The results of tests of micro heat exchanger prototype for water-water system have been presented in this paper. The heat transfer rate, the heat transfer coefficient and the pressure drop of media have been tested in the functions of hot and cold water flow rates and hot water inlet temperature.

Źródło:

Chemik; 2011, 65, 10; 983-990
0009-2886

Pojawia się w:

Chemik

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 91.

Tytuł:

Numerical heat transfer in a rectangular channel with mounted obstacle

Autorzy:

Gareh, S.

Powiązania:

https://bibliotekanauki.pl/articles/412607.pdf

Data publikacji:

2014

Wydawca:

Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN

Tematy:

laminar flow
obstacle
finite volume
simulation
convective heat transfer

Opis:

The fully-incompressible, viscous and stationary Navier–Stokes equations are solved for the laminar flow over an obstacle placed on the lower of a channel. The Reynolds number is varied from 100 to 400. In all cases studied the flow field proves to be steady. Several distinct flow features are identified: a horseshoe vortex system, inward bending flow at the side walls of the obstacle, a horizontal vortex at the downstream lower-half of the obstacle and a downstream wake containing two counter-rotating vortices. The shape and size of these flow features are mainly dominated by the Reynolds number. For higher Reynolds numbers, both the horseshoe vortex and the wake region extend over a significantly larger area. The correlation of the position of the separation and attachment point with the Reynolds number has been calculated. A detailed analysis is carried out to investigate flow pattern and Nusselt number.

Źródło:

International Letters of Chemistry, Physics and Astronomy; 2014, 19, 2; 111-119
2299-3843

Pojawia się w:

International Letters of Chemistry, Physics and Astronomy

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 92.

Tytuł:

Heat transfer in falling film evaporators during the industrial process of apple juice concentrate production

Autorzy:

Cyklis, P.

Powiązania:

https://bibliotekanauki.pl/articles/240517.pdf

Data publikacji:

2018

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

heat transfer
falling film evaporator
industrial
transport
ciepło
przemysł

Opis:

Falling film, shell-tube type evaporators are commonly used heat exchangers for the production of fruit juice concentrate. The main problem in the design of the exchanger is a reliable estimation of wall heat transfer coefficients for all effects in real operating conditions. Most literature sources for the overall heat transfer coefficients are based on laboratory measurements, where the tubes are usually short, no fouling exists and the flow rate is carefully adjusted. This paper shows the heat transfer estimated in real industrial operating conditions, compared to literature sources. Paper is based on the author’s own experience in designing and launching several evaporators for juice concentrate production into operation. As a summary, the design heat transfer coefficients are provided with relation to sugar content in juice concentrate.

Źródło:

Archives of Thermodynamics; 2018, 39, 3; 3-13
1231-0956
2083-6023

Pojawia się w:

Archives of Thermodynamics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 93.

Tytuł:

Identification of fouling deposited on the heat transfer surfaces of the steam power plants heat exchangers

Autorzy:

Hajduk, T.

Powiązania:

https://bibliotekanauki.pl/articles/241825.pdf

Data publikacji:

2016

Wydawca:

Instytut Techniczny Wojsk Lotniczych

Tematy:

steam power plant
heat exchanger
heat transfer surface deposit
spectral analysis

Opis:

The term “fouling” refers to a substance, which settles on the heat transfer surface and causes the rise of thermal resistance to the heat transfer process. Sometimes, fouling is regarded as deposit but that term should be only used to fouling in the form of solid. Taking the traditional division of matter states as a criterion for fouling classification, there are three sorts of fouling: the solid ones, e.g. boiler scale, metal oxides, mud; the liquid ones, e.g. lubricating turbine oil and the volatile ones, air as for example an inert gas. Despite maintaining the recommended methods of correction for the steam power plants working agents, such as: the feed water, the boiler water, the condensate and the water vapour, for example by using the phosphate-ammonia correction, both corrosion and deposition phenomena occur in the water and the steam sides of the heat exchanger. Recognition of the type and the amounts of deposits gathered on heat transfer surfaces of the steam power plants heat exchangers is used within the thermal-flow diagnostics and also supports the planning of overhaul and routine repair of these devices. The results of the author’s own experimental research based on the method of spectral analysis were presented in the paper. The study was carried out in order to identify the type of fouling settled on both the outer side (steam side) and the internal side (waterside) on the heat transfer surfaces.

Źródło:

Journal of KONES; 2016, 23, 4; 135-142
1231-4005
2354-0133

Pojawia się w:

Journal of KONES

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 94.

Tytuł:

Phase change heat exchangers made of pin-fins for boiling enhancement

Autorzy:

Orman, Łukasz J.
Radek, Norbert
Pietraszek, Jacek
Gontarski, Dariusz

Powiązania:

https://bibliotekanauki.pl/articles/104110.pdf

Data publikacji:

2019

Wydawca:

Stowarzyszenie Menedżerów Jakości i Produkcji

Tematy:

boiling heat transfer
microfins
microstructure
wymiana ciepła
mikrowłókna
mikrostruktura

Opis:

The paper deals with the important issue of boiling heat transfer enhancement using mechanical treatment of the heater surface. The surface has been modified in such a way that microfins have been produced. The application of such a structure leads to highly increased heat fluxes in relation to the smooth surface as has been presented and discussed in the paper. The experiments including distilled water and ethyl alcohol on the horizontal copper samples of 3 cm diameter have been considered. The heat flux value of microfinned surface was even nine times higher than the heat flux dissipated from the smooth surface without any coating. It proves a considerable enhancement of boiling with the application of the mechanically treated surfaces of heat exchangers.

Źródło:

Quality Production Improvement - QPI; 2019, 1, 1; 433-439
2657-8603

Pojawia się w:

Quality Production Improvement - QPI

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 95.

Tytuł:

Experimental and numerical study of the heat transfer and pressure drop in triangular chevron channels

Autorzy:

Dolatabadi, H.
Aghdam, A. H.

Powiązania:

https://bibliotekanauki.pl/articles/949298.pdf

Data publikacji:

2018

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

heat transfer
pressure drop
thermal enhancement factor
phase shift

Opis:

Experimental and Numerical studies were carried out on turbulent heat transfer and friction factor loss through a triangular chevron channel. For uniform wall heat flux equal 1350 (W/m²) using air as a working fluid. Reynolds number varied from 3000 to 10000, phase shifted at the range of 0≤ϕ≤180, with variation distance between chevron surfaces (5 ≤ D ≤ 35 mm). Nu increased and TEF decreased in increasing of Re. The TEF and Nu increased with closing to channel phase shift angle 90˚, the best performance was noticed on phase shift, ϕ=90º. At the end of this paper effect of distance between chevron surfaces presented, The TEF and Nu increased with decreasing to channel distance and the best performance was noticed on closing to D=5(mm).

Źródło:

Journal of Theoretical and Applied Mechanics; 2018, 56, 3; 751-763
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 96.

Tytuł:

Determination of heat flux at a solid-solid intreface

Autorzy:

Rywotycki, M.
Malinowski, Z.
Sołek, K.
Falkus, J.
Miłkowska-Piszczek, K.

Powiązania:

https://bibliotekanauki.pl/articles/356275.pdf

Data publikacji:

2019

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

continuous casting of steel
heat transfer
inverse method
rolls

Opis:

Determining the boundary conditions of heat transfer in steel manufacturing is a very important issue. The heat transfer effect during contact of two solid bodies occurs in the continuous casting steel process. The temperature fields of solids taking part in heat transfer are described by the Fourier equation. The boundary conditions of heat transfer must be determined to get an accurate solution to the heat conduction equation. The heat flux between the tool and the object processed depends mainly on temperature, pressure and time. It is very difficult and complicated to accomplish direct identification and determination of the boundary conditions in this process. The solution to this problem may be the construction of a process model, performing measurements at a test stand, and using numerical methods. The proposed model must be verified on the basis of parameters which can easily be measured in industrial processes. One of them is temperature, which may be used in inverse methods to determine the heat transfer coefficient. This work presents the methodology for determining the heat flux between two solid bodies staying in contact. It consists of two stages – the experiment and the numerical computation. The problem was solved by using the finite element method (FEM) and a numerical program developed at AGH University of Science and Technology in Krakow. The findings of the conducted research are relationships describing the value of the heat flux versus the contact time and surface temperature.

Źródło:

Archives of Metallurgy and Materials; 2019, 64, 1; 79-86
1733-3490

Pojawia się w:

Archives of Metallurgy and Materials

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 97.

Tytuł:

Analysis and design of thermo-mechanical interfaces

Autorzy:

Dems, K.
Mroz, Z.

Powiązania:

https://bibliotekanauki.pl/articles/202338.pdf

Data publikacji:

2012

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

multiphase structures
sensitivity analysis
optimization
heat transfer
thermo-elasticity

Opis:

An elastic structure subjected to thermal and mechanical loading with prescribed external boundary and varying internal interface is considered. The different thermal and mechanical nature of this interface is discussed, since the interface form and its properties affect strongly the structural response. The first-order sensitivities of an arbitrary thermal and mechanical behavioral functional with respect to shape and material properties of the interface are derived using the direct or adjoint approaches. Next the relevant optimality conditions are formulated. Some examples illustrate the applicability of proposed approach to control the structural response due to applied thermal and mechanical loads.

Źródło:

Bulletin of the Polish Academy of Sciences. Technical Sciences; 2012, 60, 2; 205-213
0239-7528

Pojawia się w:

Bulletin of the Polish Academy of Sciences. Technical Sciences

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 98.

Tytuł:

Computational fluid dynamics simulation of heat transfer from densely packed gold nanoparticles to isotropic media

Autorzy:

Radomski, Piotr
Ziółkowski, Paweł
de Sio, Luciano
Mikielewicz, Dariusz

Powiązania:

https://bibliotekanauki.pl/articles/1954995.pdf

Data publikacji:

2021

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

heat transfer
gold nanoparticles
glasses
polymers
computational fluid dynamics

Opis:

This work aims to determine and compare heat generation and propagation of densely packed gold nanoparticles (Au NPs) induced by a resonant laser beam (532 nm) according to the Mie theory. The heat flux propagation is transferred into the materials, which here are: silica glass; soda-lime-silica glass; borosilicate glass; polymethyl methacrylate (PMMA); polycarbonate (PC); and polydimetylosiloxane (PDMS). This analysis aims to select the optimum material serving as a base for using photo-thermoablation. On the other hand, research focused only on Newtonian heat transfer in gold, not on non-Fourier ones, like the Cattaneo approach. As a simulation tool, a computational fluid dynamics code with the second-order upwind algorithm is selected. Results reveal a near-Gaussian and Gaussian temperature distribution profile during the heating and cooling processes, respectively. Dependence between the maximum temperature after irradiation and the glass thermal conductivity is observed confirming the Fourier law. Due to the maximum heating area, the borosilicate or soda-lime glass, which serves as a base, shall represent an excellent candidate for future experiments.

Źródło:

Archives of Thermodynamics; 2021, 42, 3; 87-113
1231-0956
2083-6023

Pojawia się w:

Archives of Thermodynamics

Dostawca treści:

Biblioteka Nauki

/5

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Skocz do pozycji: 99.

Tytuł:

Effect of heat transfer correlation on wet cylinder liner temperature distribution when converting an old engine into a turbocharged engine

Autorzy:

Trung, Kien Nguyen

Powiązania:

https://bibliotekanauki.pl/articles/1955004.pdf

Data publikacji:

2021

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

heat transfer
correlation
turbocharged engine
cylinder liner
distribution
Supercharging

Opis:

For conventional diesel engines, two of the most widely used global correlations are due to Woschni and Hohenberg. Besides, the modern diesel engines used a new heat transfer coefficient correlation was proposed by Finol and Robinson. In Vietnam, improving engine power density is a trend of improving non-turbocharged base engines by using a supercharging system with exhaust gas energy recovery. Increasing engine power by the turbocharger is limited for two reasons: mechanical stress and thermal stress of the components surrounding the combustion chamber. In general, the heat transfer coefficient has a major effect on heat transfer rate, especially during the combustion process. So, the purpose of this study is to compare the cylinder distribution results from the simulation using the equations of Woschni and Hohenberg and compare to the experiment results when converting an old heavy-duty engine into a turbocharged engine. Results show that the cylinder distribution using Hohenberg’s correlation has a good agreement with the experiment results, especially in the case of a turbocharged engine.

Źródło:

Archives of Thermodynamics; 2021, 42, 3; 159-172
1231-0956
2083-6023

Pojawia się w:

Archives of Thermodynamics

Dostawca treści:

Biblioteka Nauki

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Skocz do pozycji: 100.

Tytuł:

Innovative method for heat transfer enhancement through shell and coil side fluid flow in shell and helical coil heat exchanger

Autorzy:

Kumar, Rajesh
Chandra, Prakash
-, Prabhansu

Powiązania:

https://bibliotekanauki.pl/articles/949948.pdf

Data publikacji:

2020

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

overall heat transfer coefficient
effectiveness
helical coil
pressure drop

Opis:

The effect of shell side and coil side volume flow rate on overall heat transfer coefficient, effectiveness, pressure drop and exergy loss of shell and helical coil heat exchanger were studied experimentally under steady state conditions. The working fluid, i.e., water was allowed to flow at three different flow rates of 1, 2, and 3 l/min on shell side (cold water) and at 1, 1.5, 2, 2.5, and 3 l/min on coil side (hot water) for each shell side flow rate at the temperatures of 298±0.4 K and 323±0.4 K, respectively. The results found that the overall heat transfer coefficient increased with increasing both shell side and coil side volume flow rates. The inner Nusselt number significantly increased with the coil side Dean number.

Źródło:

Archives of Thermodynamics; 2020, 41, 2; 239-256
1231-0956
2083-6023

Pojawia się w:

Archives of Thermodynamics

Dostawca treści:

Biblioteka Nauki

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