A research of micro-pulse tube cryocooler with displacer phase shifter

Investigations of phase shifters and power recovery mechanisms are of sustainable interest for developing Stirling pulse tube cryocoolers (SPTC) with more compact design and higher efficiency. The warm displacer type SPTC has been demonstrated with a very promising theoretical efficiency benefiting from its strong phase shifting and work recovery functions. Extending this same phase shifting approach to miniature pulse tube refrigerators may provide advantages over the other alternatives, since inertance tubes are severely limited in their phase shifting capability when the associated acoustic power decreases below 20 W. A comprehensive investigation regarding the micro-pulse tube cryocooler with a displacer phase shifter is carried out in this work, including the design of the major components of the cryocooler, theoretical analysis regarding the phase relationship in the whole displacer type cryocooler system, and 2D simulation work addressing the performance of the cryocooler systems. In the optimum phase angle conditions of the 3 mm pulse tube size cryocooler, the mass flow rate leads the pressure wave by 28.8?degrees at the regenerator warm end, and lags the pressure wave by 27.7 degrees at the regenerator cold end. A cooling power of 1.5 W at 80 K and a COP (Coefficient of Performance) of 20.96% is obtained with an input power of 7.4 W.