A POROUS METAL HEAT EXCHANGER TO COOL A MICROWAVE CAVITY

THE POWER OUTPUT OF GYROTRONS USED IN THE FUSION PROGRAM IS LIMITED BY THE COOLING OF THE MICROWAVE CAVITY. EXISTING DESIGNS CAN EXTRACT A HEAT FLUX OF 1 TO 3 KW/CM(2). THE RUSSIANS HAVE REPORTED A FLUX OF 4 TO 5 KW/CM(2) USING POROUS METAL HEAT TRANSFER. POROUS METAL HEAT TRANSFER USES A THIN POROUS LAYER OF METAL POWDER UNDER A FACESHEET, WHICH IS BONDED TO A COOLANT SUPPLY/REMOVAL PLATE. THE LARGE SURFACE AREA OF THE POROUS LAYER COMBINES WITH THE LARGE CONVECTIVE HEAT TRANSFER COEFFICIENT OF THE COOLANT FLOW THROUGH THE POROUS LAYER TO MAKE POSSIBLE THE FAVORABLE HEAT TRANSFER. POROUS METAL HEAT TRANSFER HAS BEEN DEMONSTRATED FOR MIRROR COOLING FOR THE STRATEGIC DEFENSE INITIATIVE. THIS PROJECT WOULD UTILIZE POROUS METAL HEAT TRANSFER TO ACHIEVE COOLING RATES OF 10 KW/CM(2) AND ELIMINATE MICROWAVE CAVITY COOLING AS A LIMITING FACTOR IN GYROTRON POWER OUTPUT. PHASE I IS EXPECTED TO DEMONSTRATE THE HEAT FLUX OF 5 KW/CM(2) REPORTED BY THE RUSSIANS.