Study on the establishing-process of piston offset in the helium valved linear compressor under different operating parameters

Abstract The piston offset in the helium valved linear compressor (VLC) deteriorates the cooling capacity and operation life of the Joule-Thomson (JT) refrigerator, especially in aerospace applications. To clarify the influence mechanism of operating parameters on the offset characteristic of the VLC, a relative quantitative investigation is theoretically and experimentally proposed. Based on the reliable VLC developed in our lab in the hope of using for the space infrared detector, the main parameters involving the charging pressure, operating frequency, piston displacement and valve opening are systematically studied. The offset amplitude, establishment time and start-up characteristic of the offset under different conditions are presented. The equation that contains all the operating parameters capable of describing the offset values is expressed. The polynomial fitting from the experimental data verifies the deduced equation, and further explains the interaction between the offset and the operating parameters quantitatively. This study can be an effective guidance in reducing or even eliminating the offsets to improve the performance of the VLC.