Experimental Study On Heat Transfer Characteristics Of Thermal Syphon Under Different Natural Working Fluid

The heat dissipation and cooling in the running integrate micro-electronic parts is an important research theme of micro-electronics. The higher the processing speed of computer, the more heat generating from CPU chip. If the heat can't be dissipatied effectively, the processing stability and speed will be decreased dramatically. In order to fit the demand for future high speed CPU chip whose running heat flux reaches to 100-1000W/cm2, the development of an efficient cooling technology has become the update key projects all over the world. Since its intensive heat transfer characteristics, heat pipe behaves a profound advantage in the cooling of integrated circuits. On the basis of the manufactured new aluminium heat pipe sets and research work done in the Refrigeration Lab of Chongqing University, a new thermal syphon cooling machine made of aluminium has been designed. This text is to study this kind of thermal syphon to use working fluid Methanol, Ethanol and Acetone.With experiments and theoretical analyzing, we find when the heat discharge is smaller than the entrainment limited , what influences the ability of heat-transmitting of work quality is the quantity of injection and dry limit fluid inventory, the optimum quantity of injection of the three working fluid is 8~14g ; And the delivering factor that transmission coefficient is determined by capillary limit, not the heat transmission ability of the thermal syphon. Therefore, among the three working fluid, Acetone is the best. Low wind-speed has the obvious function in heat transmission of the thermal syphon. But when the wind-speed becomes above 1m/s hereafter, wind-speed increase for the CPU thermal siphon of transmit heat the ability's gain result the deceleration. So it is considered perfect when the wind-speed is 1m/s. Through this experimentation we found that when the CPU thermal syphon cooling machine used Acetone as working fluid, wind-speed 1m/s, CPU chip caloricty 60w, its volumetric heat release rate came to 1.3×104W/(m3K). We can see than this kind of CPU thermal syphon cooling machine is the one with simple texture, easy working, low costs, reliable work and good performance.From the textual research we can know that, CPU thermal syphon cooling machine using Acetone as working fluid, wind-speed is 1m/s, CPU chip caloricty is 60w, can guarantee chip temperature does not exceeding the environment temperature above 40℃, namely can guaranteeing chip temperature generally not exceeding 80℃. It can suffice the require of the long-term movement of Pentium-Ⅳ.