Parametric analysis of miniature pulse tube cryocooler regenerators at very high frequencies using REGEN 3.3

In space applications, the Miniature Pulse Tube Cryocooler (MPTC) is widely used due to its compact design and efficient performance. The regenerator is crucial for the MPTC's performance, as it experiences maximum pressure and temperature drops. To achieve higher power density and compactness, MPTCs are being developed for high-frequency operation, which is more complex than conventional 40-60 Hz systems. This study presents a detailed numerical analysis of a high-frequency regenerator using the REGEN 3.3 software tool. The study compiled results from exhaustive simulations with varying frequencies (100-200 Hz), charge pressures (3.5-6.0 MPa), and pressure ratios (1.15-1.3), targeting a cooling load of 1 W at 80 K. The influence of these parameters on the coefficient of performance (COP), net refrigeration power, regenerator losses, ineffectiveness, pressure losses, and PV power are summarized. The findings indicate that an increase in operating frequency reduces the COP by 13% and net refrigeration by 4.4%, while higher charge pressure and pressure ratio enhance the regenerator's COP by 20.79% and 91.3%, respectively, without significantly reducing net refrigeration power (5.95%) and ineffectiveness (5.05%). A near-optimal regenerator region is identified, where moderate variations in length, mass flux at the cold end, and cold end phase angle have minimal effect on performance, providing practical guidance for MPTC design at very high frequencies of 100-200 Hz.