Small Scale Cryogenic Refrigeration Technology: Small-Scale PTR

Virtual AeroSurface Technologies, Inc. in collaboration with Georgia Tech and Raytheon Company proposes a Phase II STTR program for the development and testing of meso- and micro-scale Pulse Tube Refrigerator cryocooler systems. The Phase I program performed numerical modeling and CFD simulations of the small-scale effects (e.g., increased surface area to volume ratios with relatively greater friction and heat transfer losses, adverse heat conduction in the working fluid and solid structures, etc.) on such systems and concluded that they are feasible while a parallel effort demonstrated fabrication techniques and materials suitable for prototypes at the proposed scale. The planned Phase II research will combine these two efforts into an iterative approach of simulation-based designs followed by prototype fabrication and experimental testing allowing further refinement of the simulations to produce optimized designs at both scales. Significant effort will also be performed in the selection of housing and regenerator/heat exchanger materials and assembly mechanisms for hermeticity. Initial technology transitions will be selected and compatibility testing (outgassing, radiation hardening, etc.) of critical components will be performed. The small-scale PTRs will also be demonstrated in conjunction with a small-scale compressor developed under a separate program to show a fully functional small-scale cryocooler system.