SUMMARY

Pulse tube cryocooler (PTC) is a technology for cryogenic cooling that has no moving part in its cold-end, unlike other types of cryocoolers such as Stirling-type cryocooler and Gifford-McMahon (GM) cooler. The inherent simplicity and reliability of PTCs make them attractive for applications where long-life and reliability are critical. The dissertation focuses on the thermo-fluid aspects of PTCs in the pulse tubes and regenerators which are the most important components in a PTC. Specifically, the two major problems of pulse tubes and regenerators investigated in this research are: 1) the occurrence of convective instability under non-ideal, tilted configuration, in pulse tubes, and 2) entropy generation and losses in regenerators. Computer simulations and experiments are used to investigate the convective instability in a PTC under static and dynamic tilt conditions. A semi-analytical model was developed to estimate the entropy generation and, therefore, evaluate the efficiency of regenerators.