Experimental study on heat transfer performance of lotus-type porous copper heat sink

A special kind of micro-channel heat sink was made by using lotus-type porous (also named Gasar) metals with long cylindrical pores formed during unidirectional solidification of metal–gas eutectic system. Copper was selected as the matrix metal because of its high heat conductivity. The heat transfer performance of lotus-type porous copper heat sink with a length of 20 mm along the axial direction of pores was studied on a testing platform designed and set up in this paper. The experimental results show that the lotus-type porous copper heat sink cooled by water has excellent heat transfer performance and a heat transfer coefficient of 5 W/(cm2 K) is attainable when the porosity is 29% and mean pore diameter is 400 μm. An even larger heat transfer coefficient of 9 W/(cm2 K) can be reached after simply cutting the porous copper along the vertical direction of pore axis into four or eight equal sections alined in the direction of pore axis, because that reducing the length of porous copper heat sink along the direction of pore axis will increase the penetrative porosity, result in increase of flow rate, and then enhance the heat transfer performance of the heat sink. Thus some methods have to be taken to increase the pore length and penetrative porosity when fabricating lotus-type porous copper heat sink.