Mechanical and thermal performances of multistage flexible thermal control device: A case study in cylindrical heat pipe.

Multistage flexible heat pipe has been proved to offer advantage of large flexibility as well as low thermal resistance. However, the effects of structural parameters on the comprehensive performances of such multistage thermal control device are still unclear, particularly regarding their mechanical properties. In this paper, effect of structural parameters on the mechanical and thermal performances of bionic multistage heat pipe is investigated. Results show that the stiffness of polymer tubes primarily determines the flexibility of multistage flexible heat pipe. The heat pipe with 4 metal tubes in the adiabatic section can achieve relative large flexibility and maximum bending angle as well as the short start-up time. The bending rigidity of multistage flexible heat pipe increases from 97624.4 N mm to 293152.9 N mm when its metal ratio raises from 0 % to 80 %. The thermal resistance of multistage flexible heat pipe decreases more than 32.9 % compared to the traditional flexible heat pipe. When the flexible heat pipe remains straight, the heat transfer performance will slightly increase as the shell metal ratio increases. However, its thermal resistance will also have an additional increase when bending. These results can serve as a guide for the design of the multistage flexible thermal control device.