Influence of periodic side-to-side and heaving motions on the performance of a Stirling pulse tube cryocooler

Abstract

Cryocoolers can experience near-periodic heaving or side-to-side motion and acceleration in some applications, in particular on moving platforms. In this work, the effect of heaving and rolling (side-to-side movement) on a Stirling pulse tube cryocooler was experimentally studied. Periodic heaving and rolling motions with various amplitudes, and frequencies in the 0.2 to 0.8 Hz range were imposed on a test section using a motion platform. The test section represented a prototypical commercial pulse tube cryocooler (PTC). The PTC was tested at two different neutral positions, vertical with the cold end pointing down (ideal orientation) and vertical with the cold end pointing up (inverted). When the PTC was at vertical position with the cold end pointing down, heaving movement had no measurable influence on its performance. Furthermore, the rolling motion caused some fluctuation but less than 2% drop in the cooling power of the tested PTC. When the PTC was at inverted, upside-down position, it showed significantly more sensitivity to periodic motions. Heaving motion and rolling motion resulted in approximately 5% and 10% maximum drops in the cooling power, respectively. Rolling motion also caused larger fluctuation in cooling power, with amplitudes about 15% of the average cooling power. Increasing the frequency and the amplitude of the motions both had notable negative effects on the performance of the PTC.