Performance Enhancement for 4 K Pulse Tube Cryocoolers

Future military communication systems will utilize advanced superconductor digital electronics that will require efficient cooling at low temperatures near 4 K. We propose to improve the efficiency of pulse-tube cryocoolers by addressing the two primary performance limitations. These are operation in adverse orientations and performance of the regenerator at low temperatures. We will develop (1) a CFD model to quantify the losses associated with gravity-induced flow; and (2) an advanced regenerator that uses an innovative non-rare-earth material to achieve a very high volumetric specific heat and a novel configuration for high thermal and fluid performance. The regenerator’s large heat capacity, small void volume and low flow restriction will substantially improve the thermal efficiency of low temperature pulse-tube cryocoolers. The regenerator significantly increases a cryocooler’s net cooling and thus minimizes the impact of parasitic losses in a pulse tube at an adverse gravity orientation. In Phase I, we will analyze the performance of a pulse tube cooler at different gravity orientations, optimize the regenerator design, and identify a fabrication approach for the regenerator.