A VERY HIGH EFFECTIVENESS HEAT EXCHANGER FOR REVERSE BRAYTONCRYOCOOLERS

THERE IS AN ACUTE NEED FOR VERY HIGH EFFICIENCY HEAT EXCHANGERS IN CRYOGENIC APPLICATIONS. THE GOAL OF PHASE I IS A HEAT EXCHANGER DESIGN WITH AN EFFECTIVENESS 0.99. THE HEAT EXCHANGER GEOMETRY IS A PERFORATED, PARALLELPLATE TYPE. THE DESIGN METHODOLOGY ENTAILS EXPLICIT CALCULATION OF HEAT TRANSFER RATES AND PRESSURE DROPS BY CONSIDERING LONGITUDINAL THERMAL CONDUCTION, BOUNDARY LAYER DEVELOPMENT, PROPERTIES OF TEMPERATURE FLUIDS AND MATERIALS,PLATE ALIGNMENT, AND PLATE SPACING. CONSIDERABLE EFFORT WILL BE DEVOTED TO DETERMINING THE PLATE FIN EFFECTIVENESS, AS THIS EFFECT CAN LIMIT SIGNIFICANTLY THE OVER-ALL HEAT TRANSFER RATE. A DESIGN PROGRAM WILL BE DEVELOPED THAT CALCULATES THE HEAT EXCHANGER PARAMETERS BASED ON CONSIDERATION OF THE LISTED EFFECTS.