Thermal performance enhancement of an ultra-thin flattened heat pipe with multiple wick structure

Abstract

Low heat-transport capability has been the biggest problem that has retarded the development of ultra-thin heat pipes (UFHPs). In this study, a high-performance multiple mesh wick structure, fabricated by oxidation treatment and sintering, was proposed for enhancing the thermal performance of UFHPs. The effects of various heat inputs and flattened thicknesses on the thermal performance of the UFHPs with copper mesh wicks were investigated and analysed, and the experimental results compared with those of UFHPs with conventional sintered powder wicks. The experimental results demonstrated that the heat-transport capability of the UFHP with the mesh wick could be effectively enhanced by oxidation, and the oxidized mesh wicks had the same capillary performance as sintered powder wicks. The temperature difference of the UFHP with the oxidized mesh wick was significantly lower than that of the UFHP with the un-oxidized mesh wick and sintered powder wick under identical heat input. Moreover, the performance improvement of the UFHP with the mesh wick was more significant after treatment with chemical oxidation when the flattened thickness was larger, the ultimate heat-transport capabilities of the UFHPs with a flattened thickness of 1.2 mm increased by 6 W and 9 W, respectively, compared with those with a flattened thickness of 1.0 mm.