Biporous heat pipes for high power electronic device cooling

Abstract

A biporous heat pipe is proposed to overcome heat transfer crises in the evaporator. The two levels of pore sizes of the biporous heat pipe result in high heat pipe performance. When vaporization phenomena occur in biporous wicks, bubbles formed in the near wall layer easily escape from the porous media and the possibility of vapor blanket layer formation on the heating surface decreases. Evaporation mostly occurs on the smaller surface pores. This not only increases the heat transfer performance by extended surface and smaller pore sizes, but also increases the capillary force which enables the liquid supply. The biporous structure improves the vapor and liquid distribution in the porous media when vaporization phenomena occur in it. Thermal analysis of a solid copper heat spreader and monoporous and biporous heat pipe modules are performed. Compression of the results shows the heat transfer performance of the monoporous and biporous heat pipes are better than the solid copper spreader and the biporous heat pipe has an advantage in the relatively high heat flux range. The biporous heat pipe is very attractive for high power electronic device cooling.