Experimental study on the effect of the gas reservoir on the performance of a nitrogen-charged cryogenic grooved heat pipe

Abstract

Nitrogen-charged cryogenic grooved heat pipes require gas reservoirs to reduce their initial charging pressure. However, the effect of gas reservoir on the performance of the heat pipe has rarely been investigated. In this paper, experimental studies were conducted to analyze the effects of different gas reservoir connection positions (the evaporation section and the condensation section) and different gas reservoir volumes on the startup and steady-state operation performance of heat pipes. The results indicate that the connection position of the gas reservoir affects the pressure drop of vapor flow in the heat pipe. When the gas reservoir connected to the evaporator of the heat pipe, the vapor flow pressure drop is lower, which is more favorable for the steady-state performance of the heat pipe. Additionally, a smaller gas reservoir volume allows the heat pipe to startup at higher temperatures and pressures, which can accelerate the startup rate of the heat pipe. The selection criteria for the application of gas reservoir in cryogenic heat pipes were provided. These results can be useful for optimization design of cryogenic grooved heat pipe.