Investigation and optimization of waves motion behavior in pressure oscillating tube

In this paper, the numerical analysis model and the experimental researching system were established to analyze the waves motion of the traditional oscillating tube with one end closed. The obtained achievements are as follows: (1) Through experimental verification, the two-dimension numerical model established is effective for the research on the waves motion inside the oscillating tube. (2) The velocity of the shock wave is almost linear in the injecting process and reflecting process. However, due to the reflection and the increase of jet frequency, the energy of gas waves reduces, then the velocity of shock wave decreased slightly. (3) The running distance of contact surface inside the tube is short, and continues to decrease exponentially with the increase of jet frequency; according to the fact that the time for the contact surface exhausted from the pipe is short, taking a small proportion of the total time cycle, the method to increase the number of nozzles in the gas distributor is adopted to improve the efficiency. (4) There is an optimal matching relation between the shock waves and the nozzle structure. When the reflected shock wave reaches the entrance of oscillating tube, the entrance is just closed by the nozzle frontier, which is the condition for pressure oscillating tube to reach the extremum isentropic refrigeration efficiency.