TEMPERATURE SENSITIVE, VARIABLE AREA FLOW REGULATOR FOR JOULE-THOMSON NOZZLES

CRYOCOOLERS AND GAS LIQUEFIERS UTILIZE ISENTHALPIC EXPANSION OF COOLED GAS IN JOULE-THOMSON NOZZLES. TO EFFECTIVELY OPTIMIZE USAGE OF THE COMPRESSED GAS, A VARIABLE GAS MASS FLOW RATE IS NECESSARY. A HIGH FLOW RATE IS REQUIRED INITIALLY WITH A PROGRESSIVE REDUCTION AS THE DESIGN CONDITION IS ATTAINED AND INTERMITTENT FLOW THEREAFTER DEPENDING ON THE LOAD DEMAND. THIS PROJECT INCORPORATES INNOVATIVE APPROACHES TO ACHIEVE THIS DESIRABLE LOAD DEMAND CHARACTERISTIC IN JOULE-THOMSON NOZZLES AND ALSO TO VIRTUALLY ELIMINATE A COMMON PROBLEM OF JOULE-THOMSON NOZZLES: ORIFICE BLOCKAGE BY CONDENSED CONTAMINANTS IN THE WORKING FLUID. THESE TWO OBJECTIVES ARE ACCOMPLISHED BY THE EFFECTIVE COMBINATION OF MATERIALS HAVING DIFFERENT COEFFICIENTS OF THERMAL EXPANSION AND BY DESIGN FOR EXPANSION IN A TAPERED ANNULUS EQUIPPED WITH LABYRINTH FLOW SPOILERS (ALSO SERVING AS CATCHMENT RESERVOIRS FOR CONDENSED CONTAMINANTS). THE EFFORT IS SPECIFICALLY DIRECTED TO GAS LIQUEFIERS USED TO CONDENSE THE VAPOR BOIL-OFF FROM HYDROGEN AND OXYGEN FUELS STORED ON SPACECRAFT IN INSULATED DEWAR VESSELS AT CRYOGENIC TEMPERATURE.