Thermoregulation of Loops with Capillary Pumping for Space Use

Two-phase heat-transfer capillary pumped loops (CPL) are a promising basis for development of a new generation of thermal regulation systems of space vehicles. It is assumed that such systems will have considerably better performance characteristics than traditional one-phase ones with mechanical pumping. Experimental CPLs of various modifications with a heat-transfer capacity up to 1 kW and heat-transfer length up to 5 m filled up with freon-11, ammonia and propylene as heat-transfer agents were designed. Capillary pumps which are used in CPLs let create a pressure up to 40 kPa. They are simultaneously effective evaporative heat exchangers. CPLs are well regulated by different methods which make it possible to provide stabilization of the temperature of the capillary pump active zone on changing both heat load and conditions of heat removal to the environment. The results of terrestrial and flight tests have shown efficiency and reliability of CPLs.