Preparation and thermal properties of biomimetic polymer-based flexible ultra-thin flat heat pipe

Abstract

Inspired by the structure of the human spine, a flexible ultra-thin flat heat pipe featuring a biomimetic human spine design has been devised. This flat heat pipe, equipped with a biomimetic human spine structure, is capable of undergoing repeated bending at large angles. An experimental study was conducted to investigate the primary influencing factors. The results revealed that the optimal liquid filling ratio for the flexible ultra-thin flat heat pipe is 0.3. The dip angle is positively correlated with the heat transfer performance of the flexible ultra-thin flat heat pipe, and the bending angle is negatively correlated with the heat transfer performance of the flexible ultra-thin flat heat pipe. The maximum thermal conductivity of the flexible ultra-thin flat heat pipe can reach 1457.68 W/(m·K). The flexible ultra-thin flat heat pipe with liquid filling rate of 0.3 and bending angle of 0 degree has the fastest start-up speed. A visualized experimental platform was further designed to observe the internal flow of the working fluid within the flexible ultra-thin heat pipe in various bending states. The visual experimental results demonstrate that bending initiates the premature condensation of steam within the flexible section, and the condensed working medium subsequently generates resistance to the flow of subsequent steam, leading to an inability for the latter to be smoothly transported to the condensing section, thereby creating a vicious cycle.