Experimental study on a high frequency miniature pulse tube refrigerator with inertance tube.

It is generally considered that the use of an inertance tube in a high frequency pulse tube refrigerator (PTR) improves the phase shift between the pressure and the mass flow rate. In order to investigate the effects of inertance tubes on the performance of a miniature PTR, experiments on the high frequency miniature PTR with inertance tube, orifice and bypass have been carried out. Inertance tubes with various inner diameters of 0.5mm, 1mm, 1.5mm, 2mm and different lengths from 1m to 7m were tested. Two fine needle valves were adapted as the orifice and the bypass. The experiments were performed under a charge pressure of 2.5MPa. The operating frequency is varied from 20Hz to 50Hz. Experimental results show that the inertance tube with inner diameter of 1.5mm and length of 2m is proper for the miniature PTR at high frequency. The benefit of using only an inertance tube is not apparent in miniature PTR. The lowest temperature achieved by the PTR with inertance tube is only 107.3K, which is higher than the lowest temperature of 101.6K achieved by the bypass PTR. The miniature PTR with both inertance tube and double inlet configuration has the lowest temperature of 89K. It is also found that the bypass configuration has the function of power recovery. [ABSTRACT FROM AUTHOR]