Investigation on thermal behaviours of a methane charged cryogenic loop heat pipe

As a highly efficient cryogenic heat transfer device, cryogenic loop heat pipe (CLHP) promises great application potential in the thermal control of future space infrared detection system. In this work, a CLHP using methane as working fluid operating at 100-190 K was developed, and its thermal performance including the supercritical startup, heat transport capacity under different heat sink, power cycling characteristics, temperature hysteresis phenomenon and thermal resistance variation, was experimentally investigated. Experimental results showed that the CLHP could successfully realize the supercritical startup under various auxiliary heat loads applied to secondary evaporator, reach a various heat transfer capacity under different heat sink temperature over a 0.6 m distance, and manifest good response characteristics to the cycle of heat load applied to the primary evaporator. The temperature hysteresis phenomenon was detected and thermal resistance of the CLHP varied with increasing heat load applied to the primary evaporator, but not the same with that in heat load reverse motion.