Abstract
Pulse tube cryocoolers are more attractive than other small cryocoolers because they have no moving parts in the expander and thus have higher reliability. Stirling type pulse tube cryocooler need further improvement, on especially, regenerator. The working gas flow in the regenerator becomes a flow field with non-uniform velocity distribution accompanying the expansion and contraction flow. They cause the excessice pressure loss and reheat loss. We examined the effect of the regenerator entrance shape on the performance of pulse tube cryocooler experimentally. The effect of after-cooler end was bigger than that of cold-head end.
