An experimental study on the working characteristics of a methane-charged cryogenic loop heat pipe.

Methane-charged cryogenic loop heat pipe can realize efficient cryogenic heat transport at the temperature range of 90-190 K, which exhibits great application potential in the thermal control of future space infrared exploration system. In this work, an extensive experimental study on the supercritical startup and heat transport characteristics of a methane-charged cryogenic loop heat pipe integrated with a pulse tube cryocooler was conducted, where the effects of the auxiliary heat load applied to the secondary evaporator and was investigated. Experimental results showed that the CLHP could successfully realize the supercritical startup with an auxiliary heat load of 1.5 W. The CLHP could reach a heat transport capability of 7.5W over a distance of 0.6m corresponding to an optimum charged pressure of the working fluid. And there exists a minimum auxiliary heat load for the cryogenic loop heat pipe with primary heat load of 1W at some charged pressure. Furthermore, the mechanisms responsible for these phenomena mentioned above have been analysed and discussed qualitatively, providing a better understanding from the theoretical aspect.

充注甲烷的低温环路热管（methane-charged cryogenic loop heat pipe）可在90 K至190 K的温度区间内实现高效低温传热，在未来空间红外探测系统的热控场景中具备显著应用潜力。本研究针对集成脉管制冷机（pulse tube cryocooler）的充注甲烷低温环路热管开展了系统性实验研究，重点考察了施加于次级蒸发器（secondary evaporator）的辅助热负荷（auxiliary heat load）对其超临界启动与传热特性（heat transport characteristics）的影响。实验结果表明，该环路热管可在辅助热负荷为1.5 W的条件下顺利实现超临界启动（supercritical startup）。在工质（working fluid）最优充注压力（charged pressure）下，该环路热管可在0.6 m的传输距离内实现7.5 W的传热能力。当主热负荷（primary heat load）为1 W时，在部分充注压力下，该低温环路热管存在最小辅助热负荷阈值。此外，本文对上述现象的作用机理进行了定性分析与讨论，从理论层面为该类系统的深入理解提供了支撑。