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Tytuł:
Influence of the crack propagation velocity on heat release in compressor blades during fatigue tests
Autorzy:
Bednarz, A.
Kuźniar, M.
Powiązania:
https://bibliotekanauki.pl/articles/244568.pdf
Data publikacji:
2016
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
crack propagation velocity
notch
thermovision
turbine engine
heat distribution
Opis:
In this work, the influence of the crack propagation velocity on heat release in blade was shown. Research was be performed during fatigue test of the compressor blade. In the investigations, the blade with the V-notch was examined. The blades during experiment were entered into transverse vibration by a vibration system Unholtz-Dickie UDCO-TA-250. The crack propagation process was conducted in resonance condition. The blades were periodically bended what simulates geometry changes during operation of the engine. The main part of the work is based on research of fatigue. During investigations both the amplitude of the crack length and also the blade tip displacement were controlled. Additional velocity of crack propagation was measured by change of a crack length in time. In the same time temperature, distribution pictures were observed. The taken picture was used to exhibit the phenomenon and shown the heat propagation direction. The main results of presented investigation are both the parameters of a crack and the crack growth dynamics in the compressor blade subjected to vibrations. An additional original result of the work is connection between velocity of crack propagation and temperature distribution taken from picture. The result of above analysis can be used in determining the amount of energy released during the cracking process and evaluate the amount of energy required for the growth of a gap. In this work, the capabilities of the proposed method and the problems associated with it were defined. The results presented in this paper have theoretical and practical value.
Źródło:
Journal of KONES; 2016, 23, 1; 67-73
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
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:
Propozycja struktury algorytmu ewolucyjnego do optymalizacji kosztów pompowania w wodnych sieciach przesyłowych
Structure proposed for the evolutionary algorithm enabling optimization of pumping costs for water distribution networks
Autorzy:
Malinowski, P.
Powiązania:
https://bibliotekanauki.pl/articles/237756.pdf
Data publikacji:
2011
Wydawca:
Polskie Zrzeszenie Inżynierów i Techników Sanitarnych
Tematy:
sieć wodociągowa
sieć ciepłownicza
koszty pompowania
optymalizacja
water distribution network
heat distribution network
pumping costs
optimization
Opis:
Przedstawiono metodę optymalizacji kosztów pompowania w wodnych sieciach przesyłowych (sieć wodociągowa, cieplna itp.), która umożliwia osiągnięcie efektów ekonomicznych przy jednoczesnym zapewnieniu wymaganych warunków eksploatacyjnych. Do rozwiązania tego problemu zaproponowano metodę algorytmu ewolucyjnego, ze względu na małą wydajność obliczeniową tradycyjnych metod optymalizacyjnych. W wyniku działania takiego algorytmu otrzymuje się model sieci zmodyfikowany w stosunku do wyjściowego poprzez umieszczenie w nim zadanej liczby pomp wraz z ich wymaganą charakterystyką techniczną. Wyznaczone miejsca instalacji pomp oraz ich charakterystyki prowadzą do obniżenia niezbędnego ciśnienia zasilania, nie powodując przekroczenia granicznych wartości (minimalnego i maksymalnego) ciśnienia wody w sieci. Analiza została przedstawiona na przykładzie systemu ciepłowniczego wybranego miasta. Opisano strukturę algorytmu ewolucyjnego, umożliwiającego wyznaczenie optymalnej lokalizacji pomp w systemie. Wyniki obliczeń wykazały możliwość zmniejszenia kosztów pompowania wody w systemie ciepłowniczym.
A method is described, which enables the costs of pumping in water distribution networks (water-pipe network, heat distribution network) to be optimized effectively in economic terms under the operating conditions required. Considering the complexity of traditional optimization methods and the time-consuming computations involved, an evolutionary algorithm has been proposed to cope with this problem. With this algorithm a modified network model can be obtained, which differs from the input model in that it incorporates a given number of pumps and their technical characteristics. The defined pump installation points, as well as the technical characterization of the pumps, make it possible to reduce the feeding pressure required, without exceeding the limit values (minimal and maximal) of water pressure in the network. The analysis is presented taking a municipal heat supply system of choice as an example. The structure proposed for the evolutionary algorithm permits the optimal location of the pumps in the heating system to be determined. The calculated results substantiate the possibility of reducing the water pumping costs in a heat supply system.
Źródło:
Ochrona Środowiska; 2011, 33, 2; 59-63
1230-6169
Pojawia się w:
Ochrona Środowiska
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:
Efficiency of the heat pump cooperating with various heat sources in monovalent and bivalent systems
Efektywnosc pompy ciepla wspolpracujacej z dolnymi zrodlami ciepla w systemie mono i biwalentnym
Autorzy:
Kurpaska, S.
Latala, H.
Lapczynska-Kordon, B.
Mudryk, K.
Powiązania:
https://bibliotekanauki.pl/articles/792536.pdf
Data publikacji:
2012
Wydawca:
Komisja Motoryzacji i Energetyki Rolnictwa
Tematy:
heat pump
heat source
heat distribution
monovalent system
bivalent system
compressor heat pump
vertical exchanger
horizontal exchanger
coefficient performance
heating system
Źródło:
Teka Komisji Motoryzacji i Energetyki Rolnictwa; 2012, 12, 1
1641-7739
Pojawia się w:
Teka Komisji Motoryzacji i Energetyki Rolnictwa
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Air heating units in refinish spray booths: state of the art and propositions
Ogrzewanie powietrza w renowacyjnych kabinach lakierniczych: stan bieżący i propozycje
Autorzy:
Nikończuk, P.
Powiązania:
https://bibliotekanauki.pl/articles/310198.pdf
Data publikacji:
2016
Wydawca:
Instytut Naukowo-Wydawniczy "SPATIUM"
Tematy:
spray booth
air heat distribution system
energetic efficiency
kabina lakiernicza
system dystrybucji gorącego powietrza
efektywność energetyczna
Opis:
Energy efficiency in every part of our live is the one of the main goals of European Union this also applies spray booths. The paper presents an analysis of current state of the art of air heating units used in spray booths for refinish industry. It also presents solutions proposed by the author and the benefits arising from them. The hybrid system with recuperator and heat pump can reduce power consumption of heating unit about ten times. It will minimize six times the total power of the spray booth.
Poprawa efektywności energetycznej w każdej części naszego życia jest jednym z głównych tematów Unii europejskiej. Dotyczy to również kabina lakierniczych. Artykuł przedstawia analizę bieżących rozwiązań ogrzewania powietrza w renowacyjnych kabinach lakierniczych oraz propozycje rozwiązań opracowanych przez autora. Przedstawiono podstawowe korzyści ze stosowania proponowanych rozwiązań. Proponowany hybrydowy system ogrzewania powietrza pozwala na sześciokrotną minimalizację mocy całkowitej kabiny lakierniczej.
Źródło:
Autobusy : technika, eksploatacja, systemy transportowe; 2016, 17, 12; 1240-1243
1509-5878
2450-7725
Pojawia się w:
Autobusy : technika, eksploatacja, systemy transportowe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numeryczne modelowanie rozpływu ciepła w strefie skrawania dla stali C45
Numerical simulation of heat propagation in the cutting zone for C45 steel
Autorzy:
Bartoszuk, M.
Powiązania:
https://bibliotekanauki.pl/articles/210787.pdf
Data publikacji:
2013
Wydawca:
Wojskowa Akademia Techniczna im. Jarosława Dąbrowskiego
Tematy:
obróbka skrawaniem
skrawanie ortogonalne
temperatura kontaktu
dystrybucja ciepła
symulacje MRS
machining
orthogonal cutting
contact temperature
heat distribution
FDM simulation
Opis:
Artykuł poświęcony jest zagadnieniu przepływu ciepła w czasie skrawania ortogonalnego stali C45 ostrzem węglikowym bez powłok ochronnych. W badaniach modelowych, do wyznaczenia zmian rozkładu temperatury oraz wartości średniej i maksymalnej temperatury kontaktu, zastosowano zmodyfikowaną metodę różnic skończonych. Badano zmiany dystrybucji temperatury w strefie skrawania wynikające z różnej konfiguracji kształtu strumienia ciepła generowanego na płaszczyźnie poślizgu oraz na długości kontaktu wiór-powierzchnia natarcia. Symulacje rozpływu ciepła prowadzono w oparciu o uproszczony model przepływu ciepła zakładający liniowe źródła ciepła o zmiennej intensywności wzdłuż całej swojej długości. Wyniki symulacji porównywano z danymi literaturowymi oraz wynikami eksperymentalnymi uzyskanymi na drodze pomiaru termoparą naturalną. Otrzymano akceptowalną dokładność średniej oraz maksymalnej temperatury kontaktu, potwierdzając tym samym poprawność modeli symulacyjnych.
The paper concerns heat propagation while orthogonal cutting of C45 steel by means of the carbide cutting tool without protective coating. In the model tests, the modified finite difference method was applied for determination of changes of temperature distribution, the mean and maximum contact temperatures. The tests concerned changes of temperature distribution in the cutting zone, resulting from different shape configurations of the heat flux generated on the shear plane and at the contact length between the chip and the tool rake face. Simulations of heat propagation were based on the simplified model of the heat flow assuming linear heat sources of variable intensity along its whole length. The results of simulations were compared with the data from literature and experimental data obtained from measurements by means of natural thermocouple. Acceptable accuracy of the mean and maximum contact temperature was obtained, so correctness of the simulation models was proved.
Źródło:
Biuletyn Wojskowej Akademii Technicznej; 2013, 62, 1; 79-88
1234-5865
Pojawia się w:
Biuletyn Wojskowej Akademii Technicznej
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The analysis of tribological processes in the inking unit of the offset printing machine
Autorzy:
Pyryev, Y.
Piętak, Z. M.
Powiązania:
https://bibliotekanauki.pl/articles/386751.pdf
Data publikacji:
2013
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
printing
friction
inking unit
Laplace transform
heat distribution
roller-roler contact
drukowanie
tarcie
zespół farbowy
transformacja Laplace'a
dystrybucja ciepła
Opis:
In this paper is proposed the mathematical description of the temperature distribution resulting from the friction between the two inking rollers (one of which is made off steel and the second one has elastic layer) in the offset printing machine. So-called in printing industry steel vibrator roller perform simultaneously rotary and reciprocating motion. This reciprocating motion is the main source of the heat generation. Using the Laplace transform method for heat conduction equations with boundary conditions taking into account the real processes taking place in the inking unit in contact area we obtained and analyzed the solution that could be useful for determination and regulation of parameters in order to decrease time of process stabilization.
Źródło:
Acta Mechanica et Automatica; 2013, 7, 3; 170-174
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Methods of forecasting of stable heat regime of metal polymeric bushes of bearing of sliding operating on newton lubricant
Metody prognozowania stabilnych reżymów cieplnych dla metalopolimerowych łożysk ślizgowych w obecności smaru Newtonowskiego
Autorzy:
Pavlova, I.
Vernyaeva, L.
Vassel, N.
Powiązania:
https://bibliotekanauki.pl/articles/374881.pdf
Data publikacji:
2010
Wydawca:
Politechnika Śląska. Wydawnictwo Politechniki Śląskiej
Tematy:
stabilny reżym cieplny
łożysko
łożysko ślizgowe
gradient temperatury
rozpływ ciepła
stable temperature regime
bearing work
slide bearing
temperature gradient
heat distribution
Opis:
The purpose of this work was to develop the methods of forecasting of stable heat regime of metal polymeric bushes of bearing of sliding operating on Newton lubricant. It is shown that the most stable temperature regime of bearing work is achieved through non-dimensional temperature Θ*=0,5 in the case of low plastic lubricant (A<<1) and 0,8≤ Θ*≤0,95 in the case of high plastic lubricant(A>1).
Źródło:
Transport Problems; 2010, 5, 2; 111-117
1896-0596
2300-861X
Pojawia się w:
Transport Problems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Discretization of the stationary distribution of heat in the non-homogeneous body
Autorzy:
Bożek, B.
Powiązania:
https://bibliotekanauki.pl/articles/2049973.pdf
Data publikacji:
2004
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
elliptic partial differential equations
stationary distribution of heat
discretization method
Opis:
We give a short survey on the theory of the mixed boundary-value problem for the stationary Fourier equation in a non-homogeneous medium defined on any Lipschitz domain $\Omega \rcup \mathbb{R}^{n} (n \ge 2)$. The compatibility condition for the thermal flux has been established by the standard procedure of integration the divergence.
Źródło:
Opuscula Mathematica; 2004, 24, 1; 19-33
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
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:
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:
Calculation of distribution of temperature in three-dimensional solid changing its shape during the process
Autorzy:
Bożek, B.
Mączka, C.
Powiązania:
https://bibliotekanauki.pl/articles/255226.pdf
Data publikacji:
2005
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
parabolic partial differential equations
non-stationary distribution of heat
finite element method
Galerkin method
Opis:
The present paper suplements and continues [2]. Galerkin method for the Fourier-Kirchoff equation in the case when Omega(t) - equation domain, dependending on time t, is constructed. For special case Omega(t) rcup R2 the computer program for above method is written. Binaries and sources of this program are available on http://wms.mat.agh.edu.pl/~bozek.
Źródło:
Opuscula Mathematica; 2005, 25, 2; 169-179
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Udoskonalone sposoby akumulacji i rozdziału ciepła w instalacjach grzewczych
Improved methods of accumulation and distribution of heat in the heating systems
Autorzy:
Naskręt, L.
Powiązania:
https://bibliotekanauki.pl/articles/1819775.pdf
Data publikacji:
2009
Wydawca:
Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:
instalacja grzewcza
rozdział ciepła
akumulacja
akumulator warstwowy
heating system
distribution of heat
accumulation
layerd buffer tank
Opis:
Oszczędność energii cieplnej jest istotnym elementem strategii współczesnego budownictwa. Poszukiwanie coraz sprawniejszych i bardziej wydajnych układów cieplnych do zastosowania w budynkach o różnym przeznaczeniu, stymuluje ciągły rozwój branży ciepłowniczej. Jednym z najbardziej skutecznych kierunków opracowań naukowo-technicznych jest doskonalenie sposobów akumulacji i rozdziału ciepła [1, 5, 6]. Zagadnienie to szczególnie komplikuje się w przypadku kojarzenia zróżnicowanych, pod względem temperatury i mocy, obiegów dostarczających energię i obiegów odbiorczych w ramach jednego, zespolonego układu cieplnego[4]. Niezgodności i różnice w pracy tych obiegów kreują zjawiska, które można sklasyfikować w następujący sposób: . brak równowagi hydraulicznej i ostre sprzeczności współpracujących ze sobą obiegów; ujawnione podczas eksploatacji przewymiarowanie lub niedowymiarowanie źródła ciepła; zwiększoną częstotliwość tzw. "taktowania" (włączenia-wyłączenia, zmiany stopni mocy), kotła lub węzła cieplnego, a także poszczególnych siłowników urządzeń automatyki, skutkiem czego staje się obniżona sprawność układu, a w przypadku kotła również zwiększenie emisji substancji szkodliwych; ograniczoną zdolność wykorzystania i regulacji nadmiaru ciepła (np. kocioł na paliwo stałe; kominek); brak możliwości kojarzenia energii z różnych źródeł, o różnym potencjale energetycznym i przeznaczeniu jej do realizacji procesów grzewczych lub technologicznych założonych w obiekcie; niewykorzystanie energii strumienia powrotnego instalacji odbiorczej przy niedostatecznym rozbiorze ciepła; zwiększony czas rozruchu źródła ciepła i instalacji; wydłużoną reakcję źródła ciepła na zmieniające się parametry czynnika,zapotrzebowanie na moc w instalacji i warunki termiczne otoczenia; zmniejszenie efektywności energetycznej i ekonomicznej systemu Skutecznym rozwiązaniem w takich sytuacjach jest dynamiczne oddzielenie obiegów zasilających i instalacyjnych za pomocą rozdzielacza hydraulicznego oraz termodynamicznie uzasadnione zwiększenie pojemności zładu grzewczego w postaci akumulatora ciepła, o dokładnie określonej objętości, działającego według zasady uwarstwienia [2, 7]. Cały ten kierunek ma jeszcze sporo niewykorzystanych możliwości.
Saving the heat energy is an important element of the strategy of modern construction. The search for more efficient and more productive thermal systems for use in buildings for different purposes stimulates the continuous development of heating industry (Fig. 2, 3, 4). One of the most effective lines of such operations is improvement of the accumulation and distribution of heat (Fig.1). The issue is especially complicated in the case of associating different (in terms of temperature and power) energy supply and receiving flow section in a whole integrated heating system (Fig. 3). Effective solution in such situations is a dynamic separation of power supply and installation circuits using a hydraulic splitter and reasonable thermodynamic increase of heat transfer medium volume in heating system in the form of heat accumulator, a well-defined volume, acting according to layering rules (Fig. 4). Universal tool to solve this problem according to the authors is presented in the paper the extensive application of the principles of layered heat buffer tanks (Fig. 5). Advantages of application of improved version of stratified heat accumulators are following: decrease of size of computational power of installed main heat source; significant decrease of consumption of thermal energy in the exploited object; significant increase of thermal efficiency of the whole heating installation; possibility of association of heat sources with different energetic potential, including return streams of heating medium with inflated temperature of recycle; appeasement of hydraulic and thermodynamical incompatibilities during work of the individual circulations of heating installations; constant and long term comparable decreasing of costs of purchase of energy, at comparatively small investment outlays, which are the cost of accumulator, additional return mains, units of steering and measurement and necessary labour; achievement of ecological effect, by decrease power of heat source or sources, limitation the number of their power-ups and changes of the power stages and the possibility of association with the renewable sources of heat.
Źródło:
Rocznik Ochrona Środowiska; 2009, Tom 11; 555-570
1506-218X
Pojawia się w:
Rocznik Ochrona Środowiska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Heat dissipation and temperature distribution in long interconnect lines
Autorzy:
Gnidzińska, K.
Mey, G.
Napieralski, A.
Powiązania:
https://bibliotekanauki.pl/articles/199909.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
interconnect lines
heat dissipation
delay
temperature distribution
Opis:
Thermal and time delay aspects of long interconnect lines have been investigated. To design a modern integrated circuit we need to focus on very long global interconnects in order to achieve the desired frequency and signal synchronization. The long interconnection lines introduce significant time delays and heat generation in the driver transistors. Introducing buffers helps to spread the heat production more homogenously along the line but consumes extra power and chip area. To ensure the functionality of the circuit, it is compulsory to give priority to the time delay aspect and then the optimized solution is found by making the power dissipation as homogenous as possible and consequently the temperature distribution T (relative to ambient) as low as possible. The technology used for simulations is 65 nm node. The occurring phenomena have been described in a quantitative and qualitative way.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2010, 58, 1; 119-124
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
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:
Numerical analysis of influence of bearing material thermal conductivity coefficient on hydrodynamic lubrication of a conical slide bearing
Autorzy:
Czaban, A.
Powiązania:
https://bibliotekanauki.pl/articles/246592.pdf
Data publikacji:
2018
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
slide bearing
hydrodynamic lubrication
conical bearing
heat conduction
pressure distribution
Opis:
One of the main parameters affecting the hydrodynamic lubrication of slide bearings is the viscosity of lubricating oil. Many studies show, that significant changes in the viscosity of oil occur along with changes in its temperature. The influence on the temperature distribution in the lubrication gap of the slide bearing have a variety of factors, and one of them is the amount of heat exchanged between the lubricant and the environment. The temperature of the lubricating oil of operating bearing is usually higher than the ambient temperature. In addition to the convection, which occurs during the flow (heat exchange related to the oil supply and discharge system) some amount of heat is transferred to the bearing sleeve material (and also to the bearing shaft), and then it is conducted to sleeve outer surface. The amount of heat transferred through the bearing sleeve is mainly dependent on the difference of temperatures between inner and outer sleeve surfaces and also depend on the heat conduction coefficient of sleeve material. This article presents the results of modelling of the influence of amount of heat conducted through the bearing material, on the hydrodynamic lubrication of a conical slide bearing. The study concerned various values of the heat conduction coefficient of the bearing material to investigate its influence on the temperature values of lubricating oil, and thus, on its viscosity, on the distribution of hydrodynamic pressure and on the calculated values of bearing load carrying capacities and friction forces.
Źródło:
Journal of KONES; 2018, 25, 2; 89-96
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
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:
Analyzing temperature changes in the ground massif with a horizontal heat exchanger in the course of the heating season
Autorzy:
Adamovsky, R.
Neuberger, P.
Sed'ova, M.
Powiązania:
https://bibliotekanauki.pl/articles/62442.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Infrastruktura i Ekologia Terenów Wiejskich PAN
Tematy:
temperature change
ground massif
horizontal heat exchanger
heating season
heat pump
ground source heat pump
heat transfer
energy potential
ground temperature
temperature distribution
Opis:
The article is devoted to temperature changes in the ground massif with the horizontal heat exchanger as an energy source for a heat pump. The article was aimed at analyzing temperature changes in the ground massif with the horizontal heat exchanger at the beginning, in the course of and at the end of the heating season. Another aim was to analyze temperature differences in the area of the horizontal exchanger and the reference lot. The heat flow utilized in the evaporator of heat pump was extracted from the ground exchanger (nominal output at the condenser was 10.5 kW). Temperatures of the ground massif with the horizontal heat exchanger were measured in its plane in depths of 0.75 m, 0.5 m and 0.25 m. The temperature inside the ground massif on the reference lot and ambient parameters were measured as well. It is obvious that the difference of energetic potentials inside the ground massif with the heat exchanger and on the reference lot is insignificant at the beginning of the heating season. During the heating season, the difference of ground massif energetic potentials increases; at the end it is constant. The difference of temperatures in horizontal planes was not significant at the beginning of the heating season; however, it gradually increased. Maximum differences were detected in the area of the heat exchanger. In higher strata, the difference between temperatures decreases. During a major part of the heating season, temperatures at pipes of the ground exchanger were negative. This fact affected amounts of heat extracted from the ground massif.
Źródło:
Infrastruktura i Ekologia Terenów Wiejskich; 2010, 11
1732-5587
Pojawia się w:
Infrastruktura i Ekologia Terenów Wiejskich
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:
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:
Recent sea surface temperature trends and future scenarios for the Mediterranean Sea
Autorzy:
Shaltout, M.
Omstedt, A.
Powiązania:
https://bibliotekanauki.pl/articles/49032.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
Mediterranean Sea
sea surface temperature
temporal distribution
spatial distribution
climate change
heat exchange
cloud cover
variation coefficient
Źródło:
Oceanologia; 2014, 56, 3
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Temperature changes in heat pump horizontal ground source
Autorzy:
Adamovsky, R.
Neuberger, P.
Sed'ova, M.
Powiązania:
https://bibliotekanauki.pl/articles/60337.pdf
Data publikacji:
2009
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Infrastruktura i Ekologia Terenów Wiejskich PAN
Tematy:
temperature change
heat pump
ground massif
horizontal heat exchanger
heat potential
soil
thermal potential
heating period
ground temperature
temperature distribution
heat transfer
energy conservation
Opis:
The paper deals with assessment of thermal fields and temperature changes in ground massif with horizontal heat exchanger used as a heat source for a heat pump. Temperatures in the zone of the horizontal ground exchanger are compared with temperatures in a reference land. Changes of heat potential of the soil during the heating period are also assessed. Possibilities of recovery of thermal potential of the ground massif when utilizing vertical and horizontal exchangers are analyzed in the opening part of the paper. The results of the first verification indicated that average temperatures in the horizontal planes of the ground massif did not differ considerably with distance from the exchanger tube. Differences in average temperatures in reference and experimental lands confirmed sufficient heat potential of the ground massif even at the peak of the heating period. The differences in average temperatures reached up to 6.51 K in the end of the heating period while at the beginning of the heating period, the differences in average temperatures dropped to 1.35 K. The differences between maximum and minimum temperatures in the zone of the ground exchanger reached up to 1.9 K at the peak of the heating period and rose to 3.9 K at the beginning and end of the heating period. The first results of our measurements indicate the necessity of accumulation of thermal energy in the soil massif in the summer period like in case of the vertical exchangers.
Źródło:
Infrastruktura i Ekologia Terenów Wiejskich; 2009, 07
1732-5587
Pojawia się w:
Infrastruktura i Ekologia Terenów Wiejskich
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Partition of Heat in 2D Finite Element Model of a Disc Brake
Autorzy:
Grześ, P.
Powiązania:
https://bibliotekanauki.pl/articles/387286.pdf
Data publikacji:
2011
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
rozkład temperatury
hamowanie
hamulec
przewodność cieplna
partition of heat
braking
temperature distribution
Opis:
In this paper nine of formulas (theoretical and experimental) for the heat partition ratio were employed to study the temperature distributions of two different geometrical types of the solid disc brake during emergency brake application. A two-dimensional finite element analysis incorporating specific values of the heat partition ratios was carried out. The boundary heat flux uniformly distributed over the circumference of a rubbing path to simulate the heat generated at the pad/disc interface was applied to the model. A number of factors over the heat partition ratio that affects the temperature fields are included and their importance is discussed.
Źródło:
Acta Mechanica et Automatica; 2011, 5, 2; 35-41
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on heat flow in granite sample using thermal imaging camera
Autorzy:
Małek, E.
Miedzińska, D.
Niezgoda, T.
Stankiewicz, M.
Powiązania:
https://bibliotekanauki.pl/articles/242569.pdf
Data publikacji:
2016
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
thermovision
thermal imaging camera
temperature distribution
granite
aluminum foam sample
heat flow
Opis:
Research on heat flow in granite sample and sample of aluminium foam with the use of a thermal imaging camera is presented in the paper. Temperature distribution on the surface of the sample as a function of time was obtained on the basis of data from the thermal imaging camera. Thermovision is one of the most universal technology, which is applied for detection of infrared radiation. This technique allows observing and record infrared radiation emitted by objects located in the surrounding environment. This technology allows obtaining, in a short time, temperature distribution on the surface of the sample. The thermograms (pictures showing on the surface of the object) are types of photos showing temperature distribution on the tested object surface which is achieved on the base of a specified range of electromagnetic radiation. Accurate measurement of the temperature distribution on the heated granite sample surface was obtained using a thermal imaging camera FLIR SC 6000. Thermal imaging camera was connected to the computer equipped with control software FLIR ResearchIR Max. Heat source was applied in the experiment as a cast iron hotplate with high efficiency heating, gradual control and 1500W power. Obtained results showed regular temperature distribution over the surface of researched sample.
Źródło:
Journal of KONES; 2016, 23, 4; 327-333
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-25 z 57

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