Experimental Research on Thermal Performance of Ultra-Thin Flattened Heat Pipes

作者：Tang Yongle; Cao Jianguang; Wang Shuangfeng^*

来源：Journal of Thermal Science, 2022, 31(6): 2346-2362.

DOI：10.1007/s11630-022-1710-x

• ultra-thin flattened heat pipe
• liquid filling ratio
• gas-liquid phase space distribution
• thermal performance
• prediction model

Ultra-thin flattened heat pipe (UTHP) is an effective solution to solve the problem of high-power density heat dissipation in narrow space. The key factors that determine its thermal performance include: the shapes and sizes of the UTHP, the wick structure, the type of working fluid and its filling ratio. The change in the filling ratio means not only a change in the amount of the working fluid, but also a change in the space distribution of the gas and liquid phases inside the heat pipe. Therefore, it is important to explore the effect of liquid filling ratio on the thermal performance of UTHP. It can provide effective guidance for the production of UTHP. In this work, experiments were conducted on four groups of UTHPs with different mesh wicks under a series of liquid filling ratios. The results demonstrate that the volume of the filling working fluid should account for 22%-37% of the total internal volume of the UTHP to avoid deterioration of heat transfer during the operation of the UTHP. In addition, a prediction model of the evaporator temperature has been established to provide guidance for the application of UTHPs.