Imperial College London
Alternate

ProfessorChristosMarkides

Faculty of Engineering, Department of Chemical Engineering

Professor of Clean Energy Technologies
 
 
 
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Contact

 

+44 (0)20 7594 1601c.markides Website

 
 
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Location

 

404ACE ExtensionSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Van:2021:10.1016/j.ijheatmasstransfer.2021.121743,
author = {Van, den Bergh WJ and Moran, HR and Dirker, J and Markides, CN and Meyer, JP},
doi = {10.1016/j.ijheatmasstransfer.2021.121743},
journal = {International Journal of Heat and Mass Transfer},
pages = {1--19},
title = {Effect of low heat and mass fluxes on the boiling heat transfer coefficient of R-245fa},
url = {http://dx.doi.org/10.1016/j.ijheatmasstransfer.2021.121743},
volume = {180},
year = {2021}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - In-tube flow boiling at low mass and heat fluxes is of increasing interest particularly for low-concentration solar power systems, refrigerators, heat pumps, and other thermal management components and systems. In this study, the flow boiling of R-245fa was investigated experimentally for vapour qualities ranging from 0.05 to 0.90, mass fluxes of 40, 60 and 80 kg/m2s, and heat fluxes of 2.5, 5.0 and 7.5 kW/m2. Tests were done at quasi-steady-state conditions in a horizontal smooth tube with an inner diameter of 8.31 mm and a heated length of 0.8 m, at a saturation temperature of 35°C. It was found that the heat transfer coefficient was influenced by both the mass and heat fluxes. At any given vapour quality and heat flux combination, an increase in the mass flux resulted in an increase in the heat transfer coefficient. However, the magnitude of the increase and sensitivity to the mass flux was not the same in all of the test cases. Higher vapour quality cases were more sensitive to the mass flux than lower vapour quality cases, except at low heat flux conditions. In the most peculiar case, at the lowest considered heat flux of 2.5 kW/m2, severe sensitivity to mass flux was observed at vapour qualities between 0.2 and 0.3. For all other heat fluxes, the heat transfer coefficient was found to be independent of the vapour quality except when the mass flux was high, where increased vapour quality resulted in improved heat transfer coefficients. Various correlations were investigated, but none of them captured the trends for the lowest heat flux.
AU  - Van,den Bergh WJ
AU  - Moran,HR
AU  - Dirker,J
AU  - Markides,CN
AU  - Meyer,JP
DO  - 10.1016/j.ijheatmasstransfer.2021.121743
EP  - 19
PY  - 2021///
SN  - 0017-9310
SP  - 1
TI  - Effect of low heat and mass fluxes on the boiling heat transfer coefficient of R-245fa
T2  - International Journal of Heat and Mass Transfer
UR  - http://dx.doi.org/10.1016/j.ijheatmasstransfer.2021.121743
UR  - https://www.sciencedirect.com/science/article/pii/S0017931021008498?via%3Dihub
UR  - http://hdl.handle.net/10044/1/90809
VL  - 180
ER  -
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