Thermal performance of a cryogenic parallel heat pipe system

Abstract

In this study, we experimentally investigated the thermal behavior of a cryogenic parallel heat pipe system, which comprises a parallel arrangement of an N2-heat pipe and Ar-heat pipe or an N2-heat pipe and Ne-heat pipe. The heat pipes in the parallel system have common evaporator and condenser sections. We conducted preliminary experiments to investigate the individual thermal performance of heat pipes considering three working fluids, which formed the basis for analyzing the parallel heat pipe system. The experiments were performed at several condenser temperatures between 27 and 110 K for a wide range of heat loads considering various heat pipe operating states, such as the normal heat pipe operation, local dry-out, and locally frozen states. Although the tested heat pipes, manufactured by Fujikura Electronics (Thailand) ltd., were commercial heat pipes for room temperature applications, which use water as a working fluid, the working fluid was replaced with nitrogen, argon, or neon in the present experiments. The heat pipes used a composite wick comprising axial grooves and sintered metal powders. The experimental results verify that the heat pipe can be utilized even in the local dry-out state or locally frozen state. Moreover, the parallel heat pipe system can enhance the thermal performance with respect to the maximum heat transport capability, which was 29 W at an operating temperature of 87 K, and expand the operating temperature range to 24–150 K. The proposed parallel heat pipe system can be used to improve the cooling system of superconducting magnets and in other cryogenic applications.