熱音響冷凍機 パルス管低温部における流体変位・位相差が性能に及ぼす影響

Abstract

In this study, the behavior of the gas in a pulse tube is visualized using a shuttle (light resinous ball), acrylic pulse tube, and acrylic vacuum chamber. In the case of an orifice pulse tube refrigerator, the lowest temperature was 173K at 3Hz. This paper presents the influence of gas displacement and phase difference between gas displacement and pressure in a pulse tube on the performance of a pulse tube refrigerator. Experimental results show that, in the case of an orifice pulse tube refrigerator, not only must gas phase difference be magnified but also gas displacement must be optimized because larger gas displacement results in larger regenerator loss. In the case of a double-inlet pulse tube refrigerator, we observed a DC flow in the pulse tube and measured the DC flow rate under specific conditions. DC flow rate was 0.3×10-6m3/s when the Cv value of the bypass valve was 0.03. By holding down the DC flow rate to 0×10-6m3/s with the use of a check valve and DC flow control valve, the performance of the double-inlet pulse tube refrigerator was improved. Furthermore, gas displacement and phase difference could be measured under no DC flow in the double-inlet pulse tube refrigerator. Experimental results show that optimized gas displacement in the double-inlet pulse tube refrigerator is smaller than the optimized gas displacement in the orifice pulse tube refrigerator, and optimized phase difference in the double-inlet pulse tube refrigerator is larger than the optimized phase difference in the orifice pulse tube refrigerator. Therefore, the performance of the double-inlet pulse tube refrigerator is better than that of the orifice pulse tube refrigerator.