Numerical optimizing analyses of pulse tube regenerators

Based on the 1-D & 2-D combined computational model, numerical optimizing analyses on the performance of the orifice type pulse tube refrigerator (OPTR) and double-inlet type pulse tube refrigerator (DPTR) were carried out. The evolvements process of the flow field in the OPTR and DPTR were examined. The results show that in the compressor expansion process the gas separation phenomenon occurs in the pulse tube, and in the compression process, there exists the gas aggregation phenomenon. The gas velocities in the separation and aggregation interfaces are zero, so the interface is called zero interface. In a period, the zero interface will move from one end of the pulse tube to the other end, which is called zero interface effect. The zero interface effect is an important factor for the performance enhancement of the PTR. The longer the time of the zero interface effect existing in a period, the better the PTR performance. Then based on the simulation results, the mechanism analysis for the existing of zero interface effect was performed. The results show that the introduction of the orifice valve leads to the formation of zero interface effect and the introduction of the double-inlet valve could augment the zero interface effect. For the OPTR, the time of the zero interface existing is about 1/6 period and for the DPTR the existing time of the zero interface is about 1/2 period.