Development of Novel Flexible Heat Pipe with Multistage Design Inspired by Structure of Human Spine

Abstract To improve the thermal performance and expand application scope of the flexible heat pipe, a novel flexible heat pipe with multistage design is proposed which inspired by the structure of human spine. The thermal performance of bionic flexible heat pipe under different working conditions was experimentally investigated. Our results show that bionic flexible heat pipe has lower thermal resistance and better stability after bending compared with the traditional flexible heat pipe. Moreover, the bionic flexible heat pipe with 25% filling ratio has low thermal resistance and strong anti-gravity ability. Furthermore, the thermal resistance of bionic flexible heat pipe keeps about 0.57 °C/W after bending multiple times because working fluid can realize two phase cycle in bionic flexible heat pipe. In general, the thermal resistance of bionic flexible heat pipe increases with the increase of bending angle, but the change of thermal resistance is closely related to the working position during the inclined bending process, because the height difference between the evaporator and condenser has a great effect on the thermal performance of flexible heat pipe. Moreover, the maximum height of the anti-gravity section of flexible heat pipe is derived to determine the maximum bending angle range of flexible heat pipe during three-dimensional (3D) bending. This study provides a new method for the design of flexible heat pipe with high performance.