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{Guo:2023:10.1016/j.energy.2022.125845,
author = {Guo, J and Song, J and Lakshmi, Narayanan SN and Pervunin, KS and Markides, CN},
doi = {10.1016/j.energy.2022.125845},
journal = {Energy},
pages = {1--13},
title = {Numerical investigation of the thermal-hydraulic performance of horizontal supercritical CO2 flows with half-wall heat-flux conditions},
url = {http://dx.doi.org/10.1016/j.energy.2022.125845},
volume = {264},
year = {2023}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - Thermo-hydraulic characteristics of supercritical CO2 (SCO2) flows in horizontal tubes with half-wall heat-flux conditions are investigated numerically, which is a common practice such as applications in solar parabolic trough collectors, while the heat transfer performance and the underlying mechanisms have not been fully understood. In heated flows, buoyancy acts to inhibit heat transfer when the top half of the tube wall is heated, however, when the bottom half of the tube wall is heated, this inhibition is alleviated, and the synergy between the temperature gradient and velocity fields improves thanks to the secondary flow in the near-wall region at the bottom wall. As a result, the heat transfer coefficient is ∼95% higher (on average) than in the case when the top half of the tube wall is heated. When the bottom half of the tube wall is cooled, buoyancy is expected to enhance heat transfer, while the synergy between the temperature gradient and velocity fields is supressed by the secondary flow in the near-wall region at the bottom of the tube. Conversely, when the top half of the tube wall is cooled, the buoyancy effect inhibits heat transfer, while the synergy between the temperature gradient and velocity fields is improved by the secondary flow in the near-wall region at the top of the tube, which eventually leads to an increase of ∼21% (on average) in the heat transfer coefficient relative to the case when the bottom half of the tube wall is cooled. Finally, the heat transfer discrepancy due to different heat flux conditions revealed in this study are employed in a heat exchanger model, indicating that the thermal performance of this device can be increased by ∼6% through an appropriate arrangement of the hot and cold flows without additional costs.
AU  - Guo,J
AU  - Song,J
AU  - Lakshmi,Narayanan SN
AU  - Pervunin,KS
AU  - Markides,CN
DO  - 10.1016/j.energy.2022.125845
EP  - 13
PY  - 2023///
SN  - 0360-5442
SP  - 1
TI  - Numerical investigation of the thermal-hydraulic performance of horizontal supercritical CO2 flows with half-wall heat-flux conditions
T2  - Energy
UR  - http://dx.doi.org/10.1016/j.energy.2022.125845
UR  - https://www.sciencedirect.com/science/article/pii/S0360544222027311?via%3Dihub
UR  - http://hdl.handle.net/10044/1/101121
VL  - 264
ER  -
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