Microchannel heat sinks are pointed to have a great potential in cooling systems. This paper presents a systematic study to develop a microchannel heat sink to be used in cooling applications. Particular emphasis is given to PV panels cooling. A systematic experimental approach is used to optimize the heat sink geometry. Then the potential advantage of using flow boiling conditions is explored in both numerical and experimental approaches. The two-phase flow is characterized in two different sets of conditions. In the experimental approach, a constrained bubble flow was observed with a stable pattern and bubble frequency in the narrower channel. In the wider channel a bubbly flow was observed with increased bubble diameters. Numerical simulations were also performed in order to examine the first transient stages of the two-phase flow development close to the inlet of the considered microchannels assuming an initial arbitrary distribution of nucleation sites. For this purpose, a previously developed and validated numerical simulation framework was utilised. The proposed customized tool has been developed in the general context of OpenFOAM CFD Toolbox and it accounts for phase-change (boiling/condensation) as well as for Conjugate Heat Transfer between solid and two-phase flow domains. The numerical predictions reveal that the proposed tool is sensitive enough to capture the effects of channel aspect ratio, applied heat flux and applied mass flux on the generated transient bubble dynamics and the associated heat transfer characteristics and it can constitute an important tool for quantifying the underpinned complex physical mechanisms, providing further insight into the experimental observations and measurements.
|Number of pages||11|
|Journal||Applied Thermal Engineering|
|Publication status||Published - 24 Sep 2022|
Bibliographical noteFunding Information:
Authors acknowledge to Fundação para a Ciência e Tecnologia (FCT) for partially financing the research through project PTDC/EMETED/7801/2020 and to Portuguese Army – Ministério da Defesa, for financing project CINAMIL n° 02_2021 - Development of thermal management and climatization systems for CBRN equipment. Mr. Pedro Pontes also acknowledges to FCT for supporting his PhD fellowship (Ref. SFRH/BD/149286/2019).
The numerical part of this research was partially funded through the European Space Agency (ESA MAP CORA projects TOPDESS and ENCOM4). Finally, Dr. Georgoulas and Dr. Andredaki would like to specifically thank also University of Brighton for the financial support through the Rising Stars Initiative Scheme and more particularly the School of Architecture Technology and Engineering for providing simulation time in its High-performance Computing Facilities
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