Study on Heat Transfer and Fluid Flow of Reentrant Microchannels and Effects of Geometry Parameters on Its Performance

doi:10.3901/JME.2025.16.092

Abstract

Abstract: To solve the limited heat transfer performance of conventional microchannels and enhance heat transfer, single-phase heat transfer and flow characteristics of the reentrant microchannels with narrow slot upside and reentrant cavities downside are studied based on numerical simulation method. The effects of cavity diameter, slot width and slot height on their performance are explored, and the geometry parameters are optimized. It is found that with the increase in cavity diameter and slot width, the heat transfer performance of reentrant microchannels is improved, whereas slot height plays a negligible role on the heat transfer performance. The reentrant shape breaks the common continuous development of thermal boundary layer, and exerts throttling effects on the fluid flow, which induce the thinner thermal boundary layer and contributes to heat transfer enhancement. With the increase in cavity diameter and slot width, the pressure drop of reentrant microchannels decreases, whereas the pressure drop tends to increase with increasing slot height. When considering both heat transfer and pressure drop, the optimum geometry parameters of reentrant microchannels should be with the cavity diameter of 0.9 mm, slot width of 0.4 mm, and slot height of 0.2 mm. This study provides a new microchannel shape for high-performance microchannel heat sinks, and also provide valuable fundaments for the design and fabrication of enhanced microchannels.

Key words: reentrant microchannels, numerical simulation, convective heat transfer, geometry optimization

CLC Number:

TK124

DENG Daxiang, ZHANG Quanfu, ZENG Long. Study on Heat Transfer and Fluid Flow of Reentrant Microchannels and Effects of Geometry Parameters on Its Performance[J]. Journal of Mechanical Engineering, 2025, 61(16): 92-101.

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