Novel Lightweight Loop Heat Pipe Radiator for High-Power Space Systems

Abstract

High-power space systems reject a large amounts of waste heat via medium- or high-temperature radiators. For this application, the heat pipe radiator is desired for its simplicity, efficiency, and reliability. It is commonly composed of cylindrical heat pipes and planar fins. Although typically made of advanced materials with low density and high thermal conductivity, the pipe–fin combination suffers from a series of drawbacks, such as large thermal resistance in component joints, thermal expansion rate incompatibility, and high acquisition cost. This study innovates the heat pipe radiator configuration by developing an all-metal loop heat pipe (LHP) radiator. The evaporator and compensation chamber are formed in a cylindrical container with traditional sintered wick layers and a plug. The LHP applies dozens of parallel capillaries arranged in two planar arrays as condensers to spread heat to radiating panels, realizing lightweightness and efficient heat transfer. A theoretical study was performed to analyze the nonuniform liquid–vapor distribution in multicondenser lines. Experimental studies were carried out to investigate startup performance, quasi-steady-state operation, and temperature hysteresis. The proposed design is proven to be capable of fulfilling the heat rejection requirement of space systems and exhibits technical benefits over existing ones.