2006 Volume 47 Issue 9 Pages 2240-2247
Lotus-type porous copper with many straight pores is produced by precipitation of supersaturated gas when the melt dissolving gas is solidified. Lotus-type porous copper is attractive as a heat sink because a higher heat transfer capacity is obtained as the pore diameter decreases. The main features of lotus-type porous metals are as follows; (1) the pores are straight, (2) the pore size and porosity are controllable, and (3) porous metals with pores whose diameter is as small as ten microns can be produced. We developed a lotus-type porous copper heat sink for cooling of power devices. Firstly we investigated the effective thermal conductivity of the lotus copper, considering the pore effect on heat flow. Secondly, we investigated a straight fin model for predicting the heat transfer capacity of lotus copper. Finally, we examined experimentally and analytically determined the heat transfer capacities of three types of heat sink with conventional groove fins, with groove fins having a smaller fin gap (micro-channels) and with lotus-type porous copper fins. The lotus-type porous copper heat sink were found to have a heat transfer capacity 4 times greater than the conventional groove heat sink and 1.3 times greater than the micro-channel heat sink at the same pumping power.