Experimental investigation on the sintered wick of the anti-gravity loop-shaped heat pipe

The Anti-Gravity Loop-Shaped Heat Pipe (AGLSHP), designed with a special sintered wick structure, is a novel device used in electronic heat dissipation under the anti-gravity condition. Two kinds of wick structures, single-powder (SP) and continuous step-graded (CSG) structures were evaluated for design optimization. The copper powder utilized in the experiment were divided into six particle sizes (<25, 25-50, 50-75, 75-100, 100-125, and >125 μm) to investigate their influence. The results show that the heat transfer performance of the sintered wick samples changes significantly with the variation of the copper powder size. SP75-100 is the optimal particle size for single-powder sintered wick heat transfer, while CSG25-50 is the optimal particle size for the continuous step-graded sintered wick. Furthermore, the CSG sintered wick possesses better overall performance than the SP sintered wick, obtaining higher maximum operating power and lower start-up temperature.