Effect of Particle Morphology and Surface Wettability on Performance of Porous Wick and Loop Heat Pipe

Abstract

：Two kinds of loop heat pipe (LHP) porous wick with different structures are sintered by spherical copper powder and the branch copper powder witch particle size is 63.5 μm and 66.0 μm. The wettability of the porous wick is improved by chemical oxidation with H 2 O 2 . The effects of particle morphology and wettability on the porous wick liquid absorption and LHP heat transfer performance are analyzed. The results show that the working fluid has a fast climbing rate in the porous wick of branch particles.When the porous wick is hydrophilic, the suction time for distilled water climbing to 18.0 cm in the branch porous wick is about 85.0 s less than that of the spherical porous wick, and the total liquid absorption mass is larger, which is 2.0 times larger than that of the spherical porous wick. The surface layer of the porous wick has nano-scale structure oxidized by H 2 O 2 , which enhances the hydrophilicity of the porous wick and improves the liquid absorption performance. Compared with spherical particle capillary LHP, branch particle capillary LHP operates at a lower temperature. When the heating power is 280 W, the operating temperature decreases by 7.6 ℃.