Visualization experiment of wave dynamics in pressure oscillation tube

Gas Wave Refrigerator（GWR） is a kind of equipment with strong adaptability to complex working conditions. It has the advantages of high refrigeration efficiency, and can work with liquid. The pressure oscillation tube is the core part of GWR. A visual flow field measurement platform was designed to study the wave motion inside the pressure oscillation tube. The flow field splices and the schlieren technique are used to obtain the density gradient field in the tube, and the results are compared with the theoretical calculation of the two-dimensional Euler equation. The deviation between the experiment and the simulation is 3.2%. Based on the above method, experiments with different pressure ratios and rotational speeds were carried out. The experimental results show that the shock Mach number can be increased by increasing the pressure ratio or speed. When the pressure ratio increases from 1.5 to 3.0, the intensity of the shock wave and expansion wave increases significantly. When the rotational speed increases from 800 r/min to 2400 r/min, the motion path of the expansion wave system gradually bends towards the nozzle, which prolongs the time of the expansion wave at the nozzle.