Study Of Heat Transport In Pulsating Heat Pipe

With the development of electronic chips etc. to high frequency, high speed and miniaturization, the heat flux is more and more high, the problem of heat transfer has become one of the key issues that affect the performance and reliability of electronic components. Compared with traditional heat pipe, pulsating heat pipe has the advantages of simple structure, good heat transfer performance, random bending etc,it is possible to be an effective ways to solve the problem of heat dissipation of electronic components.Many factors affect heat transport of pulsating heat pipe, including the structure and size of the heat pipe, refrigerant, liquid filling ratio, angle of inclination, heating and gravity etc. Studies recently indicate that heat transfer characteristics of the pulsating heat pipe are closely related to the thermal properties of working fluid.Ethanol solution is firstly used as the working fluid of pulsating heat pipe in this study. The optimum value of filling rate and concentration of ethanol solution of pulsating heat pipe are determined. Then the graphene oxide and surfactant of sodium dodecyl sulfate(SDS) were added to enhance the heat transport performance of heat transfer performance of pulsating heat pipe filled with deionized water or ethanol. The results shows that the optimum concentration and the optimum filling rate of ethanol solution of pulsating heat pipe is 50%. The graphene oxide can enhance heat transfer performance of pulsating heat pipe filled with deionized water, and tiny effects on enhancing heat transfer performance of pulsating heat pipe filled with ethanol. This influence is closely related with power. For pulsating heat pipe filled with deionized water, when the heating power is less than 20 W, the enhancement effect of graphene oxide is weak; when the heating power is 30 ~ 60 W, the enhancement effect is strong, about 3.71 ~11.33%.With the increase of heat power, the enhancement effect of graphene oxide is obviously increased. But when the heating power is up to 80 W, the heat transfer performance of heat pipe weak, probably due to the deposition of graphene oxide. Surfactant sodium dodecyl sulfate(SDS) can enhance the heat transfer performance of pulsating heat pipe with deionized water. The higher the concentration, the stronger the enhancement effect. But the effective working range and enhancement region of the heat pipe will decrease. The enhancement effect of SDS on heat transfer performance of pulsating heat pipe with deionized water affected by power. With the increase of heat power, enhancemnet first increase and then decrease; when the power is large enough, it will weaken the heat transfer performance of the heat pipe. The higher the concentration, the power required is smaller. The enhancemnt effect of SDS on the heat transfer performance of heat pipe filled with ethanol solution is strong. However, the enhancemnt effect of SDS on heat transfer performance of pulsating heat pipe closely related to power. When the heating power is 20 ~ 60 W, the enhancement effect is obvious, can increase 5.4~13.74%. SDS can increase ethanol heat pipe vibration frequency, reduce amplitude, and can form a stable pulsating flow faster.