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Research on the mechanism of heat transfer enhancement in microchannel heat sinks with micropin fins
Author(s) -
Xie Hong,
Yang Bo,
Zhang Shuyi,
Song Moru
Publication year - 2020
Publication title -
international journal of energy research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.808
H-Index - 95
eISSN - 1099-114X
pISSN - 0363-907X
DOI - 10.1002/er.5135
Subject(s) - microchannel , nusselt number , pressure drop , heat transfer , reynolds number , mechanics , fin , heat transfer enhancement , flow visualization , vortex , wake , materials science , vorticity , particle image velocimetry , turbulence , physics , flow (mathematics) , composite material
Summary In this paper, the pressure drop and heat transfer features of a microchannel applying micropin fins are investigated by numerical simulations and experiments. The microchannel, which is 20‐mm long, 2.7‐mm wide, and 0.3‐mm deep, is fabricated with copper and consisted of staggered diamond micropin fins. The visualization experiments, by means of the advanced technology micro‐particle image velocimetry (PIV), are conducted to discuss the mechanism of heat transfer by analysing the flow regimes. Meanwhile, 3D‐coupled numerical simulations are applied for the combination with experiments in this research. It is found that the vortex‐wake flow is stable at Reynolds number ( Re ) = 0 to 300, and a steady recirculating zone can be observed in the wake, where a pair of symmetrical vortices is formed. All the time, the vortex‐wake flow is unstable at Re = 300 to 650. Under this situation, it is due to the decrease of vorticity that the Nusselt number ( Nu ) is not significantly increased as it was expected. Thus, when Nu in the pin fin microchannel is predicted, the vorticity should be considered as well as turbulent kinetic energy ( TKE ). Furthermore, comparative study was carried out based on the mechanism proposed in this study among three kinds of microchannel with different fins, including staggered circular pin fins (CPF), square pin fins (SPF), and diamond pin fins (DPF).