Experimental study on improving the heat transfer performance of large-diameter thin flattened heat pipes

Theoretically, when flattened to the same thickness, thin flattened heat pipes made from thin-walled cylindrical heat pipes with larger diameters have better thermal performance, but the conventional wick structures cannot meet their high-performance thermal requirements. In this study, to improve the heat transfer performance of large-diameter thin flattened heat pipes, composite sintered wick structures with spiral woven mesh and different mesh sizes of orthogonal woven mesh were designed and fabricated. The sizes were 150, 200, and 250 mesh. Four types of wick structures were developed to investigated the effects of the weaving mesh size and the composite sintering of the orthogonal woven mesh on heat transfer performance. The results demonstrated that the sample with the 200-mesh orthogonal woven mesh sintered wick exhibited the most pronounced improvement in thermal performance. The maximum heat transport capacity of the sample was found to be 46 W, representing an increase of 91.67 % compared with the sample utilizing the spiral woven mesh wick. Additionally, the evaporation resistance decreased by 56.24 %, and the total thermal resistance decreased by 53.40 %. These findings are highly conducive to the economic fabrication and performance improvement of large-diameter thin flattened heat pipes.