液氢温区单级高频多路旁通型脉冲管制冷机

为了既能降到液氢温区又能确保制冷机的温度稳定性，开展了仅采用长颈管，不使用双向进气进行调相的单级高频多路旁通型脉冲管制冷机的实验研究。首先用数值计算的方法获得了多路旁通开度是否最佳的判据。研制出的制冷机在充气压力1.73MPa,输入电功220W时，无负荷最低制冷温度能够降到23.6K，为目前所报道的在没有双向进气时单级高频脉冲管制冷机获得的最低温度。在达到稳定状态后，制冷机性能稳定，温度波动幅值小于0.1K。在220W输入电功下，能够在29.2K获得0.516W，34.3K获得1.0W的制冷量。

Single-stage High Frequency Multi-bypass Pulse Tube Cryocooler Operating in Liquid Hydrogen Temperature

In order to get the cooling temperature to the liquid hydrogen temperature and guarantee the temperature stability at the same time, experimental investigation on single-stage high frequency multi-bypass pulse tube cryocooler (PTC) without double-inlet is carried out. A criterion that determines whether the opening of the multi-bypass is optimum or not, is achieved by numerical simulation firstly. At present, the cooler has reached the lowest temperature of 23.6K with an electric input power of 220W, which is the reported lowest temperature for single-stage high frequency PTC without double-inlet. The fluctuations are below 0.1K after reaching its stable state, which is much smaller than that of other double-inlet PTCs. The cooler typically provides 0.516W at 29.2K and 1.0W at 34.1K with the input power of 220W.