Experimental investigation of pressure drop across regenerator at cryogenic temperature

The pulse tube cryocoolers use stainless steel wire meshes (SS 400) as regenerative heat exchangers. A regenerator should have minimum pressure drop, high heat transfer area, high heat capacity, etc. The data available on the pressure drop when subjected to cryogenic temperatures and temperature gradient is limited. The regenerator in the actual cryocooler has a high-temperature gradient. Previously an experimental setup was made to study the pressure drop in the SS 400 wire mesh used in a pulse tube cryocooler (PTC) at room temperature. The obtained data was used to calculate the hydrodynamic parameters required for the ANSYS simulations. The experimental and simulation results were compared and showed good agreement with experimental values. The present work involves the testing of the regenerator for pressure drop when subjected to a high temperature gradient. The setup consists of a regenerator whose one end is cooled to the cryogenic temperature to create a large temperature gradient representing the actual case encountered in a cryocooler with the use of external cryocooler cold temperature. The experimental setup is used to study the effect of pressure drop at different power inputs, different charge pressures, and temperatures across the heat exchanger length. Also, the study is extended to different lengths of regenerators.