定向凝固多孔Cu热沉传热性能的实验研究

EXPERIMENTAL RESEARCH ON HEAT TRANSFER PERFORMANCE OF DIRECTIOANLLY SOLIDIFIED POROUS COPPER HEAT SINK

利用定向凝固多孔Cu制备了气孔呈定向规则排布的多孔Cu热沉,对沿孔长方向长度20 mm热沉的传热性能进行了实验研究.实验结果表明,定向凝固多孔Cu热沉具有优异的传热性能,当气孔率为29%,平均孔径为400μm时,热沉的换热系数可以达到5 W/(cm^2·K),沿孔长垂直方向将定向凝固多孔Cu切割成沿孔长方向排列的2段后,其换热系数可以提高到6.5 W/(cm^2·K).这说明当定向凝固多孔Cu沿孔长方向的长度较大时,通孔率降低限制了热沉的传热性能.

Porous copper with long cylindrical pores has been fabricated by unidirectional solidification of metal-gas eutectic system,which can be used to manufacture a special kind of micro-channel heat sink.The heat transfer performance of the directionally solidified porous copper heat sink with a length of 20 mm along the axial direction of pores was studied.The experimental results show that the directionally solidified porous copper heat sink has excellent heat transfer performance and a heat transfer coefficient of 5 W/（cm^2·K） is attainable when a porosity is 29%and mean pore diameter is 400μm,and it shows a larger heat transfer coefficient of 6.5 W/（cm^2·K） after cutting the porous copper along the vertical direction of pore axis into two sections alined in the direction of pore axis.Increasing the length of porous copper heat sink along the direction of pore axis will reduce the penetration ratio of pores and then weaken the heat transfer performance of the heat sink.Thus some methods have to be taken to increase the pore length and ratio of penetrating pores when fabricating directionally solidified porous copper heat sink.