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Tytuł:
Heat Flux Distribution Estimation for CSP Applications
Autorzy:
Stokos, Konstantinos
Votyakov, Evgeny
Papanicolas, Costas
Powiązania:
https://bibliotekanauki.pl/articles/41192312.pdf
Data publikacji:
2024
Wydawca:
Politechnika Warszawska, Instytut Techniki Cieplnej
Tematy:
concentrated solar power
heat flux distribution
renewable energy
skoncentrowana energia słoneczna
rozkład strumienia ciepła
energia odnawialna
Opis:
In this paper the concept of a new method for the estimation of the heat flux distribution and the total power in CSP applications is presented. This method requires appropriate analysis of the temperature evolution on a target, or directly on a receiver. A 3-D thermal conduction model with boundary conditions to take into account the convection and radiation losses has been developed. A parametric analysis was performed and we checked how the physical parameters affect the applicability of the method. Having proven numerically the potential of this method, it was experimentally implemented in the central tower CSP plant of The Cyprus Institute at PROTEAS facilities successfully. Finally, experience gained from the numerical and experimental application of this method is discussed.
Źródło:
Journal of Power Technologies; 2024, 104, 1; 56-66
1425-1353
Pojawia się w:
Journal of Power Technologies
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Chosen possibilities of $ \overline{ \epsilon } $-fuzzy boundary elements method application in the analysis of conductivity problems with uncertainties
Autorzy:
Witek, Halina
Witek, Bernard
Powiązania:
https://bibliotekanauki.pl/articles/38705714.pdf
Data publikacji:
2023
Wydawca:
Instytut Podstawowych Problemów Techniki PAN
Tematy:
ɛ-fuzzy boundary element method
ɛ-number
fuzzy boundary element method
heat conduction
temperature distribution
object diagnosis
ɛ-metoda rozmytych elementów brzegowych
metoda rozmytych elementów brzegowych
przewodnictwo cieplne
rozkład temperatury
diagnoza obiektu
Opis:
The paper presents a methodology of solving boundary problems with uncertainty parameters based on the use of interval perturbation numbers. This methodology allows for the analysis of very complex problems with different uncertain parameters. Fuzzy Boundary Element Method (FBEM) using $ \overline{ \epsilon } $-number will be called $ \overline{ \epsilon } $-Fuzzy Boundary Element Method ($ \overline{ \epsilon } $-FBEM). Detailed discussion of the problems of computing and applications will be presented on the example of the fuzzy boundary integral equation arising from the boundary problem for the potential problems with heterogeneous, fuzzy boundary conditions of Dirichlet and Neumann type, fuzzy internal sources, fuzzy boundary and fuzzy fundamental solution. The presented methodology can be used to solve various engineering problems (e.g. in civil engineering, power engineering and others) – e.g. to analyze the temperature distribution in structural elements or elements located in the vicinity of objects or devices. In the latter case the increased temperature may be a symptom of a severe failure (e.g. power transformer overload, overexcitation or a fault) which cannot be tolerated due to the threat to the object and to the entire power system. Proposed method maybe used for electrical equipment diagnosis and in consequence as a power system failure prevention. In this paper calculation methodology is illustrated on the example of an area bounded by a square, on the left boundary of which a certain temperature is set, while on the rest of the boundaries the conditions are equal to zero. A dedicated computer program allows for the calculation of both temperature and temperature derivative for any number of boundary elements using $ \overline{ \epsilon } $-FBEM.
Źródło:
Computer Assisted Methods in Engineering and Science; 2023, 30, 4; 407-426
2299-3649
Pojawia się w:
Computer Assisted Methods in Engineering and Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Geometrical and optical analysis of small-sized parabolic trough collector using ray tracing tool SolTrace
Autorzy:
Singh, Raman Kumar
Chandra, Prakash
Powiązania:
https://bibliotekanauki.pl/articles/27312206.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
parabolic trough collector
SolTrace
Monte Carlo ray tracing method
nonuniform heat flux distribution
optical analysis
geometrical analysis
Opis:
The present work is aimed at geometrical optimization and optical analysis of a small-sized parabolic trough collector (PTC). Improving the performance of parabolic trough collectors can greatly justify the use of solar energy. An optimized curvature geometry, the location of the absorber tube, and the heat flux distribution along the circumference of the absorber tube are major features in the geometric optimization and optical modelling of parabolic trough collectors. Rim angle, aperture width, the diameter of the absorber tube, receiver position, and the optimum value of heat flux are the major parameters considered in this work for geometrical and optical analysis. The Monte Carlo ray tracing method has been adopted for analysis. The non-uniform heat flux distribution profile obtained from optical analysis of the proposed parabolic trough collector has been compared with the profile available in the literature, and good agreement has been obtained, which proves the feasibility and reliability of the model and method used for this study. An experimental new small-sized parabolic trough collector has been fabricated for the optimized rim angle of 90 deg after a successful laser light feasibility test. The effect of the absorber tube position along the optical axis on the heat flux profile was analysed and found to be substantial. Furthermore, the sensitivity analysis of the parabolic trough collector using the software applied has been discussed separately.
Źródło:
Archives of Thermodynamics; 2023, 44, 3; 35--61
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical analysis of the heating of a die for the extrusion of aluminium alloy profiles in terms of thermochemical treatment
Autorzy:
Joachimiak, Damian
Judt, Wojciech
Joachimiak, Magda
Powiązania:
https://bibliotekanauki.pl/articles/27312236.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
temperature distribution
solid component
extrusion
aluminium profiles
gas nitriding
direct
inverse
problem
heat conduction equation
Opis:
Thermochemical treatment processes are used to produce a surface layer of the workpiece with improved mechanical properties. One of the important parameters during the gas nitriding processes is the temperature of the surface. In thermochemical treatment processes, there is a problem in precisely determining the surface temperature of heat-treated massive components with complex geometries. This paper presents a simulation of the heating process of a die used to extrude aluminium profiles. The maximum temperature differences calculated in the die volume, on the surface and at the most mechanically stressed edge during the extrusion of the aluminum profiles were analysed. The heating of the die was simulated using commercial transient thermal analysis software. The numerical calculations of the die assumed a boundary condition in the form of the heat transfer coefficient obtained from experimental studies in a thermochemical treatment furnace and the solution of the nonstationary and non-linear inverse problem for the heat conduction equation in the cylinder. The die heating analysis was performed for various heating rates and fan settings. Major differences in the surface temperature and in the volume of the heated die were obtained. Possible ways to improve the productivity and control of thermochemical treatment processes were identified. The paper investigates the heating of a die, which is a massive component with complex geometry. This paper indicates a new way to develop methods for the control of thermochemical processing of massive components with complex geometries.
Źródło:
Archives of Thermodynamics; 2023, 44, 2; 159--175
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cooling and heating of the fluid in the cylindrical volume
Autorzy:
Tkachenko, Stanislav
Vlasenko, Olha
Rezydent, Nataliia
Stepanov, Dmytro
Stepanova, Nataliia
Powiązania:
https://bibliotekanauki.pl/articles/2142869.pdf
Data publikacji:
2022
Wydawca:
Centrum Badań i Innowacji Pro-Akademia
Tematy:
non-stationary heat exchange
regular thermal mode
cooling rate
heating rate
heat transfer coefficient
uneven temperatures distribution coefficient
niestacjonarna wymiana ciepła
zwykły tryb termiczny
szybkość chłodzenia
szybkość ogrzewania
współczynnik przenikania ciepła
współczynnik rozkładu temperatur
Opis:
Experimental studies of the non-stationary heat exchange in the system «environment I – body II» have been carried out. It is established that in the body II, which consists of the fluid and thin-walled metal envelope, the characteristic features of the regular thermal mode occur, i.e., cooling (heating) rate of the body II- m = const; heat transfer coefficient between the water (environment I) and body II is practically stable α1 = const; uneven temperatures distribution coefficient in the body II ψ = const. This new notion of the heat transfer regularities in the body II is planned to apply for further development of the experimental-calculation method for the forecasting of the heat exchange intensity in the compound fluid media with limited information regarding thermophysical and rheological properties.
Źródło:
Acta Innovations; 2022, 42; 15-26
2300-5599
Pojawia się w:
Acta Innovations
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Kierunki rozwoju energetyki w województwie mazowieckim w kontekście polityki klimatyczno-energetycznej Unii Europejskiej
Directions of the power engineering development in the Mazowieckie Voivodeship in the context of the European Unions climate and energy policy
Autorzy:
Wereda, Beata
Polak, Elżbieta
Powiązania:
https://bibliotekanauki.pl/articles/2046408.pdf
Data publikacji:
2022
Wydawca:
Mazowieckie Biuro Planowania Regionalnego w Warszawie
Tematy:
ciepło
energia elektryczna
gaz ziemny
odnawialne źródła energii
paliwa ciekłe
produkty naftowe
ropa naftowa
sieci dystrybucyjne
sieci przesyłowe
systemy energetyczne
distribution grids
electricity
energy systems
heat
liquid fuels
natural gas
petroleum
petroleum products
sources of renewable energy
transmission grids
Opis:
W artykule omówiono problematykę zaopatrzenia województwa mazowieckiego w energię i paliwa, w tym systemy energetyczne funkcjonujące w regionie, a także przeanalizowano zmiany, które zaszły w przedmiotowym sektorze w latach 2010–2020 (w przypadku braku danych przyjęto krótsze okresy) oraz zamierzenia rozwojowe, określone w planach przedsiębiorstw energetycznych i tzw. specustawach energetycznych: ustawie z dnia 24 kwietnia 2009 r. o inwestycjach w zakresie terminalu regazyfikacyjnego skroplonego gazu ziemnego w Świnoujściu (specustawie gazowej), ustawie z dnia 24 lipca 2015 r. o przygotowaniu i realizacji strategicznych inwestycji w zakresie sieci przesyłowych (specustawie przesyłowej) oraz ustawie z dnia 22 lutego 2019 r. o przygotowaniu i realizacji strategicznych inwestycji w sektorze naftowym (specustawie naftowej). Przedstawiono również potencjał i wykorzystanie odnawialnych źródeł energii (OZE). Wykonane analizy pozwoliły na identyfikację przewidywanych głównych kierunków rozwoju sektora energetycznego na Mazowszu, spójnych z polityką klimatyczno-energetyczną UE i Polski. W artykule wykorzystano dane pozyskane na potrzeby aktualizacji strategii rozwoju województwa mazowieckiego, opracowanej przez Mazowieckie Biuro Planowania Regionalnego w Warszawie (MBPR).
The article presents the issue of supplying the Mazowieckie Voivodeship with energy and fuels, including energy systems operating in the region, changes in the sector between 2010 and 2020 (shorter periods were used if data was not available) and the development plans, which are set in energy companies' plans and special energy acts: the Act of 24 April 2009 on the investments relating to the liquefied natural gas regasification terminal in Świnoujście (special gas act), the Act of 24 July 2015 on the preparation and implementation of strategic investments concerning transmission networks (special transmission act) and the Act of 22 February 2019 on the preparation and implementation of strategic investments in the petroleum sector (special petroleum act). The potential and the use of renewable energy sources were also presented. The analyses made it possible to indentify the main directions of energy development in Mazovia, which are coherent with the EU and Poland's climate and energy policy. The article uses data obtained for the needs of updating the development strategy of the Mazowieckie Voivodeship, prepared by Mazovian Office for Regional Planning in Warsaw (MBPR).
Źródło:
MAZOWSZE Studia Regionalne; 2022, 40; 27-54
1689-4774
Pojawia się w:
MAZOWSZE Studia Regionalne
Dostawca treści:
Biblioteka Nauki
Artykuł
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
Artykuł
Tytuł:
Formula for temperature distribution in multi-layer optical fibres for high-power fibre lasers
Autorzy:
Grábner, Martin
Peterka, Pavel
Honzátko, Pavel
Powiązania:
https://bibliotekanauki.pl/articles/2063890.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
Tematy:
high-power fibre lasers
active optical fibres
temperature distribution
heat transfer
Opis:
High power fibre lasers need to be cooled efficiently to avoid their thermal damage. Temperature distribution in fibre should be estimated during the fibre laser design process. The steady-state heat equation in a cylindrical geometry is solved to derive a practical formula for temperature radial distribution in multi-layered optical fibres with arbitrary number of the layers. The heat source is located in one or more cylindrical domains. The validity of the analytical formula is tested by comparison with static heat transfer simulations of typical application examples including octagonal double clad fibre, air-clad fibre, fibre with nonuniform, microstructured core. The accuracy sufficient for practical use is reported even for cases with not exactly cylindrical domains.
Źródło:
Opto-Electronics Review; 2021, 29, 4; 126--132
1230-3402
Pojawia się w:
Opto-Electronics Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of non-equidistant baffle spacing in a small shell and tube heat exchanger
Autorzy:
Aziz, Abdullah
Rehman, Shafique
Powiązania:
https://bibliotekanauki.pl/articles/240423.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
thermal distribution
baffle spacing
heat exchanger
turbulence modeling
CFD study
Opis:
Most of the formulations regarding the characteristics of a shell and tube heat exchanger have a common assumption; namely that the baffle plates are equidistant. This assumption fails to cater the real world scenario for defective baffles as the alteration in a shell and tube heat exchanger invalidates the equidistant baffle spacing of the plates. In this regard, a small six baffles heat exchanger was modeled in the computational fluid dynamics software package and studied by removing each baffle plate one at a time. Effect of removing each baffle plate on the temperature, pressure, heat transfer coefficient, and total heat transfer rate was recorded. It was observed that variation in the pressure drop for the same number of baffle plates varies along the axial order of the plates. The change in pressure drop due to the removal of the baffle plate near the inlet and the outlet was lowest and reaches a maximum in the axial center. It was also found that the plates below the radial center contribute higher towards the overall heat transfer as compared to those above.
Źródło:
Archives of Thermodynamics; 2020, 41, 2; 201-221
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical validation of a method determining thermal diffusivity based on a measurement of a temperature profile
Numeryczna walidacja metody wyznaczania dyfuzyjności cieplnej bazującej na pomiarze profilu temperatury
Autorzy:
Owczarek, Mariusz
Powiązania:
https://bibliotekanauki.pl/articles/208383.pdf
Data publikacji:
2020
Wydawca:
Wojskowa Akademia Techniczna im. Jarosława Dąbrowskiego
Tematy:
measurements of thermal diffusivity
temperature distribution in a building element
approximation
heat transfer
pomiar dyfuzyjności cieplnej
rozkład temperatury w elemencie budowalnym
aproksymacja
wymiana ciepła
Opis:
The knowledge of dynamic thermal properties of building elements is necessary to investigate temperature and heat flux changes in natural daily and annual cycles. The basic dynamic parameter is thermal diffusivity. A method for determining its value for real objects has been proposed. This method is based on measuring the temperature in the element’s volume and on assuming that the obtained results meet the Fourier equation. Validation by a numerical experiment was made. The wall of the building with known thermal parameters was assumed and the temperature distribution was calculated over time in the process of non-stationary heat exchange. From the results, the diffusivity value was calculated and compared with the data entered into the model. Validations were performed for several accuracy of the temperature value and for two forms of function which approximated the temperature values obtained from calculation. A preliminary analysis of errors has been carried out.
Znajomość dynamicznych własności elementów budynku jest konieczne do określania zmian temperatury i strumieni ciepła w naturalnych dziennych i rocznych cyklach. Podstawowym parametrem dynamicznym jest dyfuzyjność cieplna. Zaproponowano metodę wyznaczania tej wartości dla rzeczywistych obiektów budowlanych. Metoda bazuje na pomiarze temperatury w objętości obiektu i założeniu że wyniki pomiaru spełniają równanie Fouriera. Przeprowadzono walidację metody za pomocą eksperymentu numerycznego. Symulowano ścianę budynku o znanych parametrach cieplnych i wyznaczono zmienność temperatury w nieustalonym stanie wymiany ciepła. Z otrzymanych wyników obliczono dyfuzyjność cieplną i porównano z danymi wprowadzonymi do modelu. Walidacja została przeprowadzona dla kilku dokładności otrzymanych wyników i dwóch postaci funkcji aproksymującej wartości temperatury otrzymanych z obliczeń. Przeprowadzono również podstawową analizę błędu.
Źródło:
Biuletyn Wojskowej Akademii Technicznej; 2020, 69, 1; 15-21
1234-5865
Pojawia się w:
Biuletyn Wojskowej Akademii Technicznej
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Energy efficiency analysis of railway turnout heating system with a melting snow model heated by classic and contactless heating method
Autorzy:
Flis, Mateusz
Powiązania:
https://bibliotekanauki.pl/articles/140565.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
electrical heating
enthalpy method
experimental research
melting process
railway turnouts
thermal field
heat distribution
Opis:
Maintaining railway turnout operability is crucial for ensuring railway transport safety. Electric heating of railway turnouts is a significant technical and economic issue. The classical heating is characterised by high power consumption. For this reason, research is needed to optimise the current system. This paper presents results of a numerical analysis and of experimental researches. The numerical analysis was carried out using the ANSYS software. There was conducted a numerical comparative analysis of energy loss during heating performed using two different heaters. Including the classical method and a heater thermally insulated from a rail. In the first step, heating of a working space filled with a substitute snow model was considered. The snow-covered surface area was held within the working space of the turnout. It was assumed that the snow substitute material had thermal properties approximately the same as real light snow. It was also assumed that the material is in the solid state which would not undergo a phase change. In the next step, a real snow model that included the phase change process was taken into account. The energy efficiency and heat distribution in the turnout have been analysed and compared. The experimental researches were carried out in a physical model. The results showed that the use of a contactless heater results in creating a larger area over which emitted heat affected snow in the working space. Consequently, more snow was melted around the contactless heater than the classic one. This experimental observation supported the results of the numerical analyses presented previously.
Źródło:
Archives of Electrical Engineering; 2019, 68, 3; 511-520
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Inverse problem of selection of the theoretical cycle for the real cycle of internal combustion engine
Autorzy:
Żmudka, Zbigniew
Postrzednik, Stefan
Przybyła, Grzegorz
Powiązania:
https://bibliotekanauki.pl/articles/241593.pdf
Data publikacji:
2019
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
internal combustion engine
real cycle
theoretic cycle
heat distribution number
reconciliation algorithm
Opis:
The effectiveness of work of an internal combustion engine can be assessed by means of the energy efficiency: theoretical, internal and effective... In the problem regarding the efficiency of obtaining a work from the tested SI engine, the theoretical Seiliger-Sabathe cycle was adopted as a reference model for the real engine cycle. For comparison, the OTTO cycle was also analysed. The engine indicating allows direct determination only of internal work. However, determining the work of the theoretical cycle first requires solving the problem of selecting the parameters of the theoretical cycle, according to the real cycle of the engine (inverse problem). In order uniquely to determine the course of the theoretical Seiliger-Sabathe cycle, it is necessary to determine the parameters of the starting point and the heat distribution number. The selection of the theoretical cycle for the real cycle, within the scope of determining the number of heat distribution, is to some extent of a contractual nature. Therefore, the problem of determining the number of heat distribution was solved by two own original methods. A comparison of the real cycle with the theoretical cycle determined for it is presented.
Źródło:
Journal of KONES; 2019, 26, 2; 197-204
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simulations of the influence of the heat flux at the shaft surface of the conical slide bearing on its hydrodynamic lubrication and operating parameters
Autorzy:
Czaban, Adam
Miszczak, Andrzej
Powiązania:
https://bibliotekanauki.pl/articles/243495.pdf
Data publikacji:
2019
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
hydrodynamic lubrication
slide bearing
conical bearing
heat conduction
pressure distribution
viscosity
Opis:
The aim of this work is to investigate, how in the adopted model of hydrodynamic lubrication of a conical slide bearing, the change of the heat flux value at the bearing shaft, affects bearing operating parameters. In this research, the authors use, the known from the literature, Reynolds type equation, describing the stationary hydrodynamic lubrication process of a conical slide bearing. The analytical, solutions, that determine the components of the lubricating oil velocity vector and the equation (analytical solution of energy equation) determining the threedimensional temperature distribution in the lubrication gap, was also adopted from previous works. In order to obtain numerical solutions, the Newton’s method was used, and the derivatives in the Reynolds type equation were approximated by the finite differences. An application of the method of subsequent approximations allowed considering the influence of temperature, pressure and shearing rate on the viscosity of lubricating oil. The considerations were performed by adopting the Reynolds condition of the hydrodynamic oil film. It was tested, how the assumed value of the heat flux on the bearing shaft surface affects the values of the obtained operating parameters, i.e. the transverse and longitudinal component of the load carrying capacity, friction force and coefficient of friction.
Źródło:
Journal of KONES; 2019, 26, 4; 29-37
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of temperature distribution in the ground
Autorzy:
Larwa, Barbara
Kupiec, Krzysztof
Powiązania:
https://bibliotekanauki.pl/articles/185407.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
heat transfer
temperature distribution in the ground
heat balance at the ground
surface
wymiana ciepła
rozkład temperatury w ziemi
bilans cieplny na ziemi
powierzchnia
Opis:
Knowledge of the temperature distribution in subsurface layers of the ground is important in thedesign, modelling and exploitation of ground heat exchangers. In this work a mathematical model ofheat transfer in the ground is presented. The model is based on the solution of the equation of transientheat transfer in a semi-infinite medium. In the boundary condition on the surface of the groundradiation fluxes (short- and long-wave), convective heat flux and evaporative heat flux are taken intoaccount. Based on the developed model, calculations were carried out to determine the impact ofclimatic conditions and the physical properties of the ground on the parameters of the Carslaw-Jeagerequation. Example results of calculated yearly courses of the daily average temperature of the surfaceof the ground and the amount of particular heat fluxes on the ground surface are presented. Thecompatibility of ground temperature measurements at different depths with the results obtained fromthe Carslaw–Jaeger equation is evaluated. It was found thatthe temperature distribution in the groundand its variability in time can be calculated with good accuracy.
Źródło:
Chemical and Process Engineering; 2019, 40, 1; 123--137
0208-6425
2300-1925
Pojawia się w:
Chemical and Process Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analiza wymiany ciepła w prętach o stałym i zmiennym przekroju
Analysis of heat transfer in pin fins of constant and non-constant cross sections
Autorzy:
Wojtas, Martyna
Powiązania:
https://bibliotekanauki.pl/articles/101707.pdf
Data publikacji:
2018
Wydawca:
Politechnika Śląska. Wydział Inżynierii Środowiska i Energetyki. Instytut Techniki Cieplnej
Tematy:
przewodzenie ciepła
rozkład temperatur
metody obliczeniowe
żebra
pręty
heat conduction
temperature distribution
calculation methods
Pin Fin
Opis:
W artykule opisano metody obliczeniowe wykorzystywane do badania zjawiska przepływu ciepła. Do analizy użyte zostały wybrane kształty prętów i żeber wykonanych z materiałów o różnych właściwościach cieplnych. Stworzono model numeryczny przewodzenia ciepła analizowanych obiektów. Zbudowano stanowisko laboratoryjne do wizualizacji rozkładu temperaturyw prętach prostych oraz stożkowych z wykorzystaniem kamery termowizyjnej. Głównym celem prezentowanej pracy było sprawdzenie poprawności stosowania modelu analitycznego.Zbadano również strumienie ciepła przekazywane przez wybrane żebra. Przedstawiono wyniki różnych metod obliczeniowych oraz wyciągnięto z nich wnioski. Porównano wpływ kształtu oraz materiału prętów na wymianę ciepła i rozkłady temperatury.
The article describes the calculation methods used to study the heat transfer. Selected shapes of pin fins and materials with different thermal properties were used for the analysis. Anumerical model of heat conduction of the analyzed objects was created. A laboratory set up was built to visualize the temperature distribution of the straight pin fins and pin fins of cone profile with blunt tip using the infrared camera. The main purpose of the presented chapter of the monograph was to check the right of using the analytical model. The results and conclusions of different calculation methods were presented. The shapes and materials of fins were also compared.
Źródło:
Archiwum Instytutu Techniki Cieplnej; 2018, 4; 153-187
2451-277X
Pojawia się w:
Archiwum Instytutu Techniki Cieplnej
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 57

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