Experimental investigation of the thermal performance of a heat sink with U-shaped heat pipes

Abstract

To meet the urgent requirement of high heat flux cooling of the chips in current electronic equipment, a unique and reliable U-shaped heat pipe bonded heat sink was developed and experimentally investigated for CPU cooling in computers. This novel heat sink was bonded with air-cooled fin stacks and two U-shaped heat pipes through the base plate. In this work, the effects of relevant parameters, including orientation of the heat sink, working conditions (air velocity and ambient temperature) of the computer on the variation of CPU temperature and overall thermal resistance of the heat sink are considered. The tests indicate that the overall thermal resistance of the heat sink at orientation α = 90° is lower than that in another five orientation cases, and reaches the minimum value of 0.263 °C/W. If the operating temperature of the CPU is limited to below 70 °C, the maximum heat dissipation power of the heat sink reaches 130 W. It can be seen that the orientation and working conditions of the heat sink have significant effects on the cooling capacity which results in variation in the overall thermal resistance of the heat sink. In addition, the comparison of overall thermal resistance between the novel heat sink and a traditional CPU fin-bonded heat sink indicates that the novel heat sink provides greater reliability.