Performance Characterization of Laminar Flow in Multiple Microjet Impingement Heat Sinks

摘要

The present study investigates the thermal performance of a silicon-based multiple microjet impingement heat sink for the thermal management of electronics. A three-dimensional numerical analysis was performed on the steady incompressible laminar flow and the conjugate heat transfer in multiple microjet impingement heat sinks. One side of the silicon substrate receives a moderate heat flux of 100 W/cm~2; the other side contains the designed jet impingement system. The jet plate consists of many jet holes, so the computational domain was simplified by using symmetric boundary conditions. The effects of the design parameters such as the jet diameter, jet pitch, and standoff (that is, the distance of the nozzle exit to the heated surface) were analyzed under laminar flow conditions. Because of the low pumping power available in the micropumping system, the analysis was carried out at a low Reynolds number. The crossflow effects of the spent flow and the inline jet sweeping were investigated to determine the optimum design parameters of the heat sink. The temperature rise, Nusselt number, pressure drop, thermal resistance, and pumping power were discussed with respect to the design parameters, namely, the ratios of the jet diameter to the standoff and the jet pitch to the jet diameter. The designs with lower jet diameter to standoff and jet-pitch-to-jet-diameter ratios offer lower thermal resistances, whereas designs with higher jet-diameter-to-standoff and jet-pitch-to-jet-diameter ratios offer lower pressure drop penalties. The relationship between the overall thermal resistance and the pumping power was presented, which showed the optimal front within the design space explored in the present study.