Effect of spiral woven mesh liquid pumping action on the heat transfer performance of ultrathin vapour chamber

In this paper, ultrathin vapour chambers (UTVCs) with two kinds of wick, namely, NO.250 copper mesh + 1 spiral woven mesh (SWM) and NO.250 copper mesh, were fabricated by brazing process. Capillary rise rate experiment was carried out using infrared (IR) camera method to characterize capillary performance of wicks and verify the SWM liquid pumping action. Effect of filling rate and SWM liquid pumping action on the heat transfer performance of UTVC were studied experimentally, and a model to predict the capillary limit of UTVC was established. The results show that the average rising speed of composite wick increased by 38.89%. The optimal filling rate of composite wick UTVC and copper mesh wick UTVC were 100%, and the maximum heat transfer capacities were 6 W and 5 W, respectively. The heat transfer performance of UTVC was greatly improved by SWM liquid pumping action, the maximum heat transfer capacity of UTVC increased by 20%-60% under different filling rate. The error of growth rate caused by SWM liquid pump action between capillary limit Qcl and maximum heat transfer capacity Qmax is less than 5%.