长颈管在微型脉冲管制冷机中的应用分析

INERTANCE TUBE USED IN A MINIATURE PULSE TUBE CRYOCOOLER

长径管作为调相器应用于微型脉冲管制冷机系统时存在阻抗不匹配现象,即调相效果好时,往往脉冲管热端阻抗大小,从而使脉冲管中的压力波幅值小,蓄冷器中损失增大,制冷性能降低;用不同管径和长度的长径管作为调相器时,最低制冷温度产生在阻抗匹配区域或热端阻抗最大的区域;对于本实验中的微型脉冲管制冷机,以长颈管作为调相器时最低制冷温度为107.3 K,低于以单纯的小孔阀作为调相器时所获得的最低制冷温度,但还达不到双向进气的水平。

As phase shifters used in high frequency miniature pulse tube cryocooler (PTC), inertance tubes can cause impedance unmatching phenomenon. When the phase difference that the pressure leads the volume velocity at the hot end of the PTC is large, the impedance at the hot end is small. The low impedance reduces the amplitude of pressure in the pulse tube, and increases the losses in the regenerator. With reference to the impedance at the hot end of the orifice PTC (the opening of the orifice is optimum), the lowest temperature is obtained at the impedance matching range or at the largest impedance range when different inertance tube length are adapted as the phase shifters. The experimental results show that the benefit of using only inertance tube is unapparent in miniature PTC. The lowest temperature achieved by the PTC with inertance tube is only 107.3 K at operating frequency of 50 Hz, which is higher than the lowest temperature obtained by the double-inlet PTC.