A hybrid microchannel heat sink with ultra-low pressure drop for hotspot thermal management

Abstract

Hotspot with several orders of magnitude heat flux higher than the background areas has become a prominent issue in the thermal management of advanced electronics. In this study, a novel microchannel heat sink with ultra-low power consumption has been introduced for chip-level hotspot thermal management. The proposed IM-HM heat sink incorporates rectangular microchannels for the background zone and pin-fins for the hotspot region, configured with an upper inlet and two side outlets. Using maximum temperature, pressure drop, and temperature uniformity as key metrics, a comprehensive numerical analysis of the IM-HM heat sink at different Reynolds number were conducted based on computational fluid dynamics. Our results demonstrate that the IM-HM heat sink enhances local heat transfer capacity and exhibits better temperature uniformity compared to the traditional rectangular microchannel heat sinks. Moreover, incorporating entry chamfer and augmenting the microchannel height have been found to effectively mitigate pressure drop in microfluidic systems. Specifically, simulation results indicate that the pressure drop in the microchannel can be reduced by 63.4 and 72.3% by increasing the inlet chamfer angle and microchannel height to 500 and 1500, respectively. Notably, the optimized IM-HM heat sink yields over 98.4% savings in pumping power to achieve consistent maximum temperatures compared to traditional rectangular microchannel heat sinks, while also exhibiting smaller temperature gradient.