Experimental study on the thermal performance enhancement of a flat plate heat pipe with surface-treated metal foam wick

Flat plate heat pipes (FPHPs) offer a promising passive thermal management solution, particularly suited for the compact cooling requirements of electronic devices. In this study, FPHPs with both regular and surface-treated metal foam wicks were fabricated and experimentally tested. The start-up characteristic was first analysed using an infrared camera. Furthermore, the effect of different working fluid filling ratios, ranging from 100 % to 170 %, and five inclination angles on the thermal performance of FPHPs was analysed. Finally, the performance enhancement of the proposed FPHPs was evaluated through comparison with similar designs reported in the literature. The results show that the optimal filling ratio is 160 %. Under an average evaporation temperature limit of 80 °C, the thermal resistance of FPHPs with regular and surface-treated metal foam wicks was 0.0158 and 0.008 °C/W, respectively, at the input power of 500 W. Moreover, compared to copper, the effective thermal conductivity of the FPHP with a surface-treated metal foam wick improved by factors of 14, 73 and 373 under anti-gravity, horizontal and gravity-assisted conditions, respectively. Compared to similar FPHPs in the literature, the peak effective thermal conductivity achieved in this study is 6.5 to 16 times higher in both gravity-aligned and horizontal conditions. These findings highlight the superior performance of surface-treated metal foam wicks, making them a promising alternative for heat pipes applications.