HEAT TRANSPORT CIRCUITS

TO EFFICIENTLY (IN TERMS OF SIZE, WEIGHT AND COMPLEXITY) MANAGE THE THERMAL SYSTEMS ON-BOARD SPACECRAFT, NASA HAS EXPLOITED THE THERMAL CHARACTERISTICS OF TWO-PHASE FLOW THERMAL CONTROL NETWORKS. SYSTEM CONCEPTS, DEVELOPED TO DATE, INCLUDE THE USE OF COMPLEX SENSOR CONTROLLED MODULATING VALVES TO REGULATE THE TRANSPORT OF HEAT FROM SPACECRAFT MODULES TO CENTRAL RADIATORS FOR REJECTION. THISSYSTEM HAS SEVERAL BENEFITS INCLUDING GOOD GROUND TESTABILITY, DESIGN FLEXIBILITY AND GOOD POTENTIAL INTEGRATION WITH SINGLE-PHASE LOOPS. HOWEVER, THE REQUIREMENT FOR SENSOR ACTIVATED CONTROL VALVES AND THE NEEDFOR A LIQUID SUCTION LINE ON THE CONDENSING PLATES ADDS COMPLEXITY AND WEIGHT TO THE SYSTEM. THE PROPOSED DEVELOPMENT OF A CENTRIFUGAL, TWO-PHASE PUMP FOR INCLUSION IN A SIMPLIFIED THERMAL CONTROL NETWORK WILL REDUCE THE REQUIRED WEIGHT, MINIMIZE COMPLEXITY AND MAXIMIZETHE GROWTH CAPABILITY OF THE SPACECRAFT SYSTEM. THE PUMP WILL BE CAPABLE OF MOVING LIQUID, GAS OR TWO-PHASE FLUIDS AND WILL ELIMINATE THE REQUIREMENT FOR A LIQUID SUCTION LINEOR SENSOR ACTIVATED MODULATING VALVES. THE PUMP IS OF A NEWTYPE IN WHICH THE LIQUID FLOW IS AUTOMATICALLY SEPARATED FROM THE GAS FLOW AT THE PUMP ENTRANCE. SEPARATE ROTOR PASSAGES HANDLE THE TWO FLUIDS. A PROTOTYPE PUMP WILL BE DESIGNED, BUILT AND TESTED AND THE GENERATED DATA, IN COMBINATION WITH SEMI-EMPIRICAL ANALYSIS TECHNIQUES, WILL SUPPLY SUFFICIENT INFORMATION FOR THE CONCEPTUAL DEVELOPMENT OF THE TWO-PHASE PUMP THERMAL MANAGEMENT SYSTEM.