Study of flow and heat transfer characteristics and structural optimization of parallel microchannel heat sink

Abstract

This study conducted a comprehensive analysis of the flow-boiling heat transfer characteristics and structural optimization for Microchannel Heat Sinks (MCHS). The modified numerical model, based on the extended RPI wall boiling model, was validated against experimental data, showing satisfactory accuracy in predicting heat transfer coefficients and dryout phenomena across a mass flux range of 282 to 1033 kg/(m²s) and heat flux levels up to 116 W/cm². The research findings indicate that microchannel structure significantly influences vapor phase generation and distribution, and elevated heat flux can lead to a decline in heat transfer performance due to complete evaporation within the channels. The trapezoidal structure of the inlet collection tank induced vortices, which increased flow resistance and decreased flow rate in the initial sections of the channels, causing localized heat accumulation. The use of transverse grooves in the microchannels reduced the flow velocity standard deviation by 70 % and enhanced the average heat transfer coefficient by 30.9 %, effectively alleviating localized high temperatures. While the optimized structure improved overall performance, especially at lower flow rates, a performance decline was observed at higher flow rates. These results contribute to the development of a numerical model applicable to a broader range of flow boiling processes and offer a viable structural optimization strategy designed to enhance thermal management within electronic devices.