Fabrication and characterization of pure-metal-based submillimeter-thick flexible flat heat pipe with innovative wick structures

In this study, a novel flexible and thin flat-plate heat pipe is fabricated and its thermal performance is characterized experimentally. The heat pipe considered in this study is made of copper-only, and employs an innovative mesh-type wick structure with nanostructured superhydrophilic surface. A single-layered copper woven mesh with nanostructured superhydrophilic surface is used as the liquid wicking structure, whereas a triple-layered coarse mesh with bare copper surface serves for vapor transporation and mechanical support against the high vacuum pressure. The fabricated heat pipe is flexible, suggesting that it can be used in many engineering applications. In addition, an analytic model for predicting the thermal resistance and the maximum heat transfer rate is developed. It has been shown that the nanostructured superhydrophilic surface can bring about a significant enhancement in the thermal performance compared with that with conventional base copper surface. Based on the results from the experiment and the analysis, the effect of wick structure on the thermal performance of the heat pipe is discussed.