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Wyszukujesz frazę "heat transfer coefficient" wg kryterium: Temat


Wyświetlanie 1-5 z 5
Tytuł:
Thermal performance of corrugated plate heat exchanger using ethylene glycol as test fluid
Autorzy:
Sreedhar Rao, Battula
Keerthana Reddy, Chittireddy
Meena, Pullurwar
Kishore Kumar, Sriramoju
Powiązania:
https://bibliotekanauki.pl/articles/1819182.pdf
Data publikacji:
2020
Wydawca:
Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:
corrugated plate heat exchanger
overall heat transfer coefficient
effectiveness
Reynolds number
współczynnik przenikania ciepła
efektywność
liczba Reynoldsa
Opis:
This paper reports an experimental comparative thermal analysis of a flat plate heat exchanger and corrugated plate heat exchanger (CPHE) of different corrugation angles using ethylene glycol as test fluid. The experiments were carried out in counter current mode using water as hot fluid at 75°C. Design of each plate provided with eleven thermocouple sensors to determine the temperatures, in which seven were used to measure the surface temperature of plate and four were used to measure the inlet and outlet bulk temperature of cold and hot fluids. The mass flow rate of test fluid, varied between 0.5 to 4 liters per minute and corresponding steady state temperatures is measured. Using experimental readings, temperature difference between the inlet and outlet streams (∆T), logarithmic mean temperature difference (LMTD) and overall heat transfer coefficient (U) are determined. The obtained ∆T and U values of corrugation angles (30°, 50°) of CPHE were compared with those of flat plate heat exchangers. For corrugation angle of 30° and 50°, the ∆T and U values increases with increase of mass flow rate of the fluid. The turbulence in the flow increases due to increase in the corrugation angle, which results in the enhancement of heat transfer. Moreover, thermal effectiveness (ε) is estimated using NTU method and compared for all the plates. As the NRe values gradually increases, ε decreases for flat plate and CPHE (θ = 30° and θ= 50°). At low NRe value of 114, observed a maximum ε (≅0.998) value for corrugated angle of 50°. There is adequate contact time between the cold and hot fluids at low Reynolds number, so maximum rate of heat transfer is possible, as a result ε values are high.
Źródło:
Journal of Mechanical and Energy Engineering; 2020, 4, 2; 167--172
2544-0780
2544-1671
Pojawia się w:
Journal of Mechanical and Energy Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of heat transfer coefficient during refrigerant condensation in vertical pipe minichannel
Autorzy:
Bohdal, T.
Kruzel, M.
Sikora, M.
Powiązania:
https://bibliotekanauki.pl/articles/95295.pdf
Data publikacji:
2017
Wydawca:
Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:
heat transfer coefficient
heat flux density
minichannel
vapor quality
współczynnik przenikania ciepła
gęstość strumienia ciepła
minikanał
jakość pary
Opis:
This article presents the results of experimental research of R404A, R407C and R410A high-pressure refrigerants condensation in vertical pipe minichannels with an internal diameter d below 2,5 mm. The study determined the local and average heat transfer coefficient in the full range of vapor quality, x= 1-0. On the basis of experimental investigations, the dependence of heat transfer coefficient on the vapor quality x, the mass flux density G and the channel internal diameter d was obtained.
Źródło:
Journal of Mechanical and Energy Engineering; 2017, 1, 1; 65-70
2544-0780
2544-1671
Pojawia się w:
Journal of Mechanical and Energy Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An investigation of heat transfer coefficient during refrigerants condensation in vertical pipe microchannel
Autorzy:
Bohdal, T.
Kruzel, M.
Sikora, M.
Powiązania:
https://bibliotekanauki.pl/articles/95255.pdf
Data publikacji:
2017
Wydawca:
Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:
heat transfer coefficient
pressure drop
heat flux density
microchannel
vapor quality
współczynnik przenikania ciepła
spadek ciśnienia
gęstość strumienia ciepła
mikrokanał
stopień suchości
Opis:
This article presents the results of experimental research of R404A, R407C and R410A high-pressure refrigerants condensation in vertical pipe microchannels with an internal diameter dw below 1 mm. The study determined the local and average heat transfer coefficient in the full range of vapor quality, x = 1-0. On the basis of experimental investigations, the dependence of heat transfer coefficient on the vapor quality x, the mass flux density G and the channel internal diameter dw was obtained.
Źródło:
Journal of Mechanical and Energy Engineering; 2017, 1, 2; 163-169
2544-0780
2544-1671
Pojawia się w:
Journal of Mechanical and Energy Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental studies on the effect of the enhancemet of the heating surface on the heat transfer coefficient for boiling in closed volume
Autorzy:
Grabowski, M.
Błachnio, E.
Powiązania:
https://bibliotekanauki.pl/articles/95221.pdf
Data publikacji:
2018
Wydawca:
Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:
boiling
boiling on enhanced surfaces
heat transfer coefficient
Intensification of heat exchange
LabView
wrzenie
wrzenie na wzmocnionych powierzchniach
współczynnik przenikania ciepła
intensyfikacja wymiany ciepła
Opis:
This article presents the results of experimental research on the effect of enhancing the heating surface on the heat transfer coefficient for boiling in a closed volume of ethyl alcohol and isopropyl alcohol. The aim of the research was determination of the impact of heat surfaces enhancements by applying circular cavities on heat transfer coefficient and on vapor structures formation during boiling. The study involved three brass samples with diameters equal to 50 mm, with different enhancements of the heating surface by drilled blind cavities. The research includes investigation of sample without cavities, sample with 133 circular cavities of diameter of 2 mm and sample with 61 circular cavities of diameter of 3 mm. On the basis of the research, the influence of the investigated heat exchange surface enhancement on the intensity of heat exchange was determined. The author’s own interface in the LabView environment for controlling and acquiring measurement data was developed. The boiling process was recorded with a high-speed camera, and based on the obtained video images, the recorded images were analyzed to determine the void fraction. The heat flux density, heat transfer coefficient were calculated and comparative diagrams of the obtained measurement results were made.
Źródło:
Journal of Mechanical and Energy Engineering; 2018, 2, 2; 121-130
2544-0780
2544-1671
Pojawia się w:
Journal of Mechanical and Energy Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research methods in the study of heat transfer coefficient during flow in minichannels
Autorzy:
Tychanicz-Kwiecień, Maria
Grosicki, Sebastian
Powiązania:
https://bibliotekanauki.pl/articles/1819147.pdf
Data publikacji:
2021
Wydawca:
Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:
heat transfer coefficient
minichannels
heat and mass transfer analogy
limiting current technique
thermal balance method
współczynnik przenikania ciepła
minikanały
analogia wymiany ciepła i masy
prąd graniczny
bilans cieplny
Opis:
The paper presents the specification of research methods commonly encountered in the studies of heat transfer processes in minichannels. In particular the following methods have been emphasized: electrochemical limiting current method as well as the thermal balance method. In thermal balance method the mean heat transfer coefficient is determined by the set of experimental thermal measurements of the investigated heat exchanger. In turn, limiting current method is based on heat and mass transfer analogy. The discussed research methods have been implemented on two specially designed and constructed test facilities with compact minichannel heat exchangers, which have been presented and described in details. In order to validate the designed setup, the preliminary experimental measurements of two minichannel heat exchangers with hydraulic diameter of 2 mm and rectangular cross sections during single-phase liquid flows have been carried out. In further perspective it is planned to extend the experimental studies of minichannel heat exchangers and to compare the results obtained by both methods described.
Źródło:
Journal of Mechanical and Energy Engineering; 2021, 5, 1; 59--68
2544-0780
2544-1671
Pojawia się w:
Journal of Mechanical and Energy Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-5 z 5

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