Study On Sonic Jet Oscillator And Refrigeration Performance Of Gas Wave Tube

On the background of the static gas wave refrigerator,the performance of sonic jet oscillator and gas wave tube has been investigated by CFD numerical simulation and experiment.Aiming at the low refrigeration efficiency caused by gas leakage at the outlet of the gas wave tube and reflected shock wave in the tube,the connection structure between the jet oscillator and the gas wave tube and the structure of the gas wave tube have been optimized respectively.The work and main conclusions of this paper are as follows:(1)Establish the calculation model of sonic jet oscillator,define the indicators to measure the performande of the jet oscillator and optimize the geometric size of the sonic jet oscillator.Based on optimited structure,the influence of the length of the sonic tube on the performance of the oscillator and the correlation among the performance paremeters have been studied.Within the pressure range studied in this paper,the oscillation frequency and the ratio of switching time to period of the jet are inversely proportional to the length of the sonic tube,and the total pressure retention rate and return rate of the jet increase with the increase of the length of the sonic tube;the gas backflow at the outlet of the jet oscillator is one of the main reasons to maintain the pressure difference between two control ports;increasing the relative pressure difference is beneficial to increase the total pressure retention rate and reduce the ratio of switching time to period.(2)The connection structure between the jet oscillator and the gas wave tube has been optimized according to the change of gas leakage rate and the refrigeration efficiency of the gas wave tube with the jet frequency.During the ejection,the gas leakage rate of the four outlet structures fluctuates with the increase of jet frequency,and the gas leakage rate of the front inclined outlet is always lower;due to the mixing of clod and hot gases,the refrigeration efficiency calculated according to the time average temperature of the gas during a cycle is always lower than the value during the exhaust phase;with the increase of the jet frequcency,the refrigeration efficiency shows an increasing trend of fluctuations,and the front inclined outlets on both sides can reduce the degree of mixing of cold and hot gases;based on the front inclined outlet,reducing the ration of the diameter of the jet oscillator outlet to the gas wave tube inlet can further reduce the gas leakage rate and the degree of mixing of hot and clod gases.(3)By analyzing the flow wave diagram in the gas wave tube,moving the end cavity of the gas wave tube to the middle can effectively reduce the intensity of the feflected shock wave and improve the refrigeration efficiency of the gas wave tube;when the middle cavity is combined with the end cavity and closed the end,the refrigeration efficiency of the gas wave tube is further improved and the fluctuation range is reduced.