Thermal performances of a heat pipe with a flexible helical adiabatic section

Conventional heat pipes are limited in axial deformability, restricting their application in flexible thermal management. In this study, a flexible helical heat pipe with an elongation ratio of up to 120% was designed and experimentally investigated. The optimum filling ratio was 30%, at which the minimum thermal resistance reached 0.8 °C/W under the heating power of 16 W and elongation ratio of 120%. The optimum inclined angle was 45°, and increasing the elongation ratio enhanced the heat transfer performance. Moreover, the thermal resistance variation remained within approximately 0.1 °C/W after repeated stretching, demonstrating excellent operational stability.