关键词: 膨胀制冷, 流动, 制冷效率, 激波, 数值模拟, 预测

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