Theoretical and experimental investigations on the supercritical startup of a cryogenic axially Ω-shaped grooved heat pipe

Abstract

The successful supercritical startup of a cryogenic grooved heat pipe is the premise for its normal operation, and the startup time determines the working efficiency of the payload. Based on this demand, a supercritical startup model of grooved heat pipe is established in the paper. The model applies more practical boundary conditions of the condensation section, without the need of knowing the temperature change of condenser in advance. With known performance curve of the cryocooler, the startup performance of heat pipe can be predicted, including the temperature distribution, startup time, etc. The predicted results by the model showed good agreement with the startup experiment results of the cryogenic grooved heat pipe. Additionally, the effects of different condenser lengths and structural parameters on the startup of heat pipe were analyzed by using the model. The results show that longer condenser length, larger groove diameter can accelerate the flow rate of condensate and the startup process. The influence of the groove depth to width of an Ω-shaped grooved heat pipe and a trapezoidal grooved heat pipe was also compared. This model provides a theoretical basis for the design and optimization of cryogenic grooved heat pipe.