液氮温区单级大功率斯特林型脉管制冷机工作特性研究（英文）

Operating characteristics of a single-stage Stirling-type pulse tube cryocooler with high cooling power at liquid nitrogen temperatures

目的:探索充气压和运行频率等工作特性对大功率脉管制冷机最低制冷温度、制冷量以及回热器温度不均匀性的影响,期望进一步提升制冷机工作性能。方法:1.通过理论计算模拟工作频率在40–70 Hz,充气压力在1.5–2.5 MPa下工作特性对制冷机性能的影响;2.实验研究充气压力为1.7–2.4 MPa,并在谐振频率附近工作时制冷机性能以及回热器温度不均匀性随充气压力、运行频率以及输入功率的变化。结论:1.制冷机运行在1.9–2.1 MPa充气压力下,因平衡了制冷温度和焓流损失,故能取得优异性能,且每一个充气压力对应一个最优的工作频率;2.通过优化充气压力和工作频率,脉管制冷机能够达到46.9 K的最低制冷温度,此时工作频率为56.5 Hz,充气压力为2.0 MPa。在8.9 k W输入功率下制冷机能够在72 K时提供304 W制冷量。

The operating characteristics are important for design and optimization of pulse tube cryocoolers, in particular for those with high cooling power, which up to now have been seldom extensively investigated. In this study, the dependence of cooling performance on the charge pressure and operating frequency has been investigated, both numerically and experimentally. A numerical model based on Sage software was established. Experiments were performed on a home-made single-stage high power Stirling-type pulse tube cryocooler（SPTC） working at liquid nitrogen temperatures. The results revealed that each charge pressure corresponds to an optimum frequency with respect to compressor and regenerator efficiency. A lower charge pressure results in a higher cryocooler efficiency, but the delivered maximum p V power is significantly reduced due to the stroke limit of the pistons in the linear compressor. The influence of operating characteristics on the temperature non-uniformity in the regenerator was also investigated. By optimizing the charge pressure and frequency, the minimum no-load temperature was decreased to 46.9 K at 56.5 Hz and 2.0 MPa. A cooling power of 300 W at 71.8 K was measured with an electrical input power of 8.9 k W.