Experimental And Numerical Investigation Of The Heat Dissipation Performance Of Heat Sink With U-shaped Heat Pipes For Computer CPU Cooling

With the rapid development of 5G telecom technology and large scale computing centres,the thermal management of the microprocessor(CPU)and related equipment are still facing unprecedented opportunities and challenges.To address the urgent requirement of high heat flux cooling of the chips in current electronic equipment and ensure that it works within the normal temperature range,a unique and reliable U-shaped heat pipe bonded heat sink was developed and experimentally investigated for CPU cooling in computers.This kind of heat sink uses a sintered capillary copper core structure,and the working medium is condensed and refluxed to the evaporation area with the aid of gravity.The heat sink has the advantages of simple structure,easy processing,good stability and high reliability,so it is one of the important methods to solve the heat dissipation of electronic chips in high heat flux.This novel heat sink was bonded with air-cooled fin stacks and two U-shaped heat pipes through the base plate.In this work,an experimental device was built to investigate the heat transfer characteristics of heat pipes heat sink.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.In addition,the professional thermal analysis software ICEPAK is used to simplify the model of the designed U-shaped heat pipe radiator;the boundary conditions,physical parameters and control equations of the model are determined,and the working conditions of the heat pipe are analysed based on the experimental test results.The overall thermal resistance of the new heat pipes heat sink and the traditional finned radiator for CPU cooling is compared.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 of0.263 ℃/W.If the operating temperature of the CPU is limited to below 70 ℃,the maximum heat dissipation power of the heat sink reaches 130 W.The reason is that gravity has an important influence on the heat dissipation capacity of the heat pipes heat sink: when the heat sink is arranged in the positive U direction,it will assist the working fluid inside the heat pipe return to the heat source area to the greatest extent,and the heat sink shows the greatest heat transfer capacity and the lowest thermal resistance.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 overall thermal resistance of the newly heat pipes heat sink is compared with that of the traditional finbonded heat sink for CPU cooling through experiments and numerical simulation.The test results showed that the thermal performance of the heat sink differed from that of the finbonded heat sink and the heat sink transferring heat only via heat pipes,and had a greater reliability.