Thermal Performance Evaluation of Space Radiator for Single-Phase Mechanically Pumped Fluid Loop

This paper presents the experimental and analytical results of a heat rejection system consisting of a single-phase mechanically pumped loop and a space radiator. It has been developed for future crewed exploration missions to provide a large amount of heat dissipation capability. The radiator consists of a honeycomb radiator, eight aluminum pipes inserted through the honeycomb core, and two aluminum manifolds joined at both ends of the eight pipes. A graphite sheet is attached to the back of the aluminum skin, facing deep space to improve the thermal diffusivity in the in-plane direction. Silverized Teflon (R) tapes are put on the surface of the skin on the deep-space side, and the surface of the opposite skin is covered with multilayer insulation. A gap between the radiator surface and the flow channel protects against micrometeoroids and orbital debris. A thermal vacuum test was conducted to evaluate the thermal performance of the radiator. The coolant was HFE7200, and its flow rate was varied from about 50 to 200 kg/h. More than 50 temperatures across the radiator surface were measured for each case. Thermal Desktop (R) and SINDA/FLUINT software were used to develop the thermal mathematical model, which was correlated with the test results and evaluated through thermal analysis. The fin efficiency of the radiator increased with the mass flow rate of the coolant, reaching 0.9 or higher.