Development of a Rectifying Interface for a Hybrid Pulse‐Tube/Reverse‐Brayton Cryocooler

A hybrid cryogenic refrigeration cycle that combines a turbomachine‐based, reverse‐Brayton lower stage with a pulse‐tube upper stage avoids the inherent losses associated with a regenerator at low temperature and therefore has the potential for high performance. One of the key technical issues relative to the successful development of this cryocooler is the integration of an oscillating flow regenerative system with a continuous flow recuperative system. This integration requires a rectifying interface composed of check valves and buffer volumes operating at cryogenic temperature.This paper describes the effect of the interface performance on the system‐level performance. The resulting performance targets are translated into component‐level requirements and used to optimize the check valve geometry. Test results from experiments with the interface integrated with a pulse‐tube are presented and compared to model predictions. The implications of the results relative to the design of a prototype, hybrid cryo...