Abstract: The offset angle of gas wave refrigerator is one of the most important parameters affecting the refrigeration efficiency. In this study, the optimal offset angle corresponding to the opening state of oscillating tube is analyzed by numerical methods. The numerical results, theoretical calculations and experiments are combined to explore the method for predicting the optimal offset angle and analyze the influence of offset angle on the refrigeration efficiency. Under given condition, when the shock wave reaches the end of the oscillating tube and half of the tube is contacted with the high temperature port at the same time, the offset angle of gas wave refrigeration is the optimal. The optimal offset angles determined by experimental data have the same trends with theoretical calculations, increasing with the angle and rotation speed, but the values differ considerably from the theoretical results. The optimal offset angles calculated by numerical simulation agree well with the experimental results, with the error less than 1%. When the rotation speed of gas wave refrigeration is lower than that with the optimal offset angle, the refrigeration efficiency decreases linearly with the reduction of rotation speed. When the rotation speed is faster than that speed, the refrigeration efficiency increases linearly with the reduction of rotation speed. With the change of rotation speed, the absolute values of linear fitting curve slope of rising and falling of the refrigeration efficiency is almost equal, which lies in the range of 0.009—0.012.

Key words: expansion refrigeration, flow, refrigeration efficiency, shock wave, numerical simulation, prediction

摘要： 气波制冷机的偏角是影响其制冷效率的重要参数.首先通过数值方法对最优偏角对应的振荡管开启状态进行定量分析;然后,将数值结果与理论计算和实验相结合,探讨气波制冷机最优偏角的预测方法,并对偏角影响气波机制冷效率的规律进行分析.对于一个确定工况,当激波运动到振荡管右端,振荡管与高温出口喷嘴呈半开半闭状态时,对应的偏角为气波制冷机的最优偏角.实验得到的最优偏角随转速的增加而增大,符合理论分析结果,但两者的结果相差较大.数值方法确定的最优偏角与实验吻合较好,误差在1%以内.当气波机转速小于最优偏角对应的转速时,制冷效率随转速降低线性减小;当转速大于最优偏角对应的转速时,制冷效率随转速降低线性增大;其中,随转速升高和降低,制冷效率的线性拟合曲线斜率的绝对值基本相等,在0.009～0.012之间.

关键词: 膨胀制冷, 流动, 制冷效率, 激波, 数值模拟, 预测