Numerical study on thermal and hydraulic performance of a stacked-plate jet-impingement/microchannel heat sink

Abstract

This paper presents a stacked-plate jet impingement microchannel (SP-JIMC) heat sink with highly-dense micro-fins and numerically investigates the thermal and hydraulic performance with single-phase water as coolant. Comparative analysis with the parallel microchannel heat sink and the micro-gap heat sink indicates that the SP-JIMC can achieve a better cooling performance and improve the temperature uniformity. With the inlet water temperature of 300 K and flow rate of 1 L/min, SP-JIMC has a thermal resistance of 0.45 cm2⋅K/W and a pressure drop of 208.2 Pa, and the maximum temperature difference is 2.2 K under 100 W/cm2 over a span of 35 mm. When the flow rate is increased to 10 L/min, the thermal resistance decreases to 0.21 cm2⋅K/W, and the pressure drop increases to 5085.9 Pa. The heat transfer analysis shows the micro-fins dissipate 77.5 % with a flow rate of 1 L/min. As the flow rate increases to 10 L/min, the jet impingement heat transfer is enhanced and the percentage of heat transfer over micro-fins drops to 56.2 %. Parametric study is performed to investigate the influence of structural parameters on the heat transfer characteristics. The results show the thermal performance is improved by increasing jet length and separator thickness, and reducing separator gap. The lowest thermal resistance is achieved at a jet width of 0.35 mm when the combined effects of jet impingement and micro-fins reach the optimum situation. In order to further improve the thermal performance of SP-JIMC, dual-side micro-fins and convex/concave impinged surfaces are simulated. The results show that adding the micro-fins on the out-flow plate can increase the heat transfer percentage over fins by 9.4 % and reduce the thermal resistance to 0.39 cm2⋅K/W under a flow rate of 1 L/min. The maximum heat transfer capacity is achieved when the inlet flow rate 35 L/min under 300 W/cm2 heat flux, the average temperature of the heating surface is 349.5 K, the pressure drop is 55.1 kPa and the thermal resistance is 0.165 cm2⋅K/W.