Study On The Oscillation Of Sonic Oscillator And Application

Jet oscillating gas wave refrigerator, a kind of gas expansion refrigeration equipment, can separate the gas into hot and cold part by the motion of the shock wave and expanding wave using the jet oscillator to generate oscillation jet's periodical injection into oscillating tube with one-closed end. So the refrigeration can be realized. The prominent advantage of this facility is that it doesn't need extra energy supply and there is no moving part, just a simple static seal. At present, the isentropic refrigeration efficiency of the jet oscillating refrigerator is at a low level and could not satisfy requirement of natural gas's industrial production.The performance of the jet oscillating gas wave refrigerator, using a sonic oscillator, is investigated by numerical simulation and experiments in the current paper. The main research work and achievements are as following:(1) The properties of wall-attaching jet flow are studied. The mathematical model is established to numerical simulate the flow field of wall-attaching jet flow. Emphasis is placed on analysis of effects on the wall-attaching jet flow of the element's geometrical sizes and operating conditions. It is concluded that it is conducive to jet flow wall-attached to set the splinter, not conducive to increase the expansion ratio, the width of the nozzle and decrease the potential difference, of small effect to change the parameters (e.g. the inlet pressure and the length of the controlling tube).(2) The oscillating process of gas wave refrigerator is studied. The flow field of gas wave refrigerator in oscillating process and the pressure changes of the controlling tube and the oscillating tube are analyzed. The time of jet flow injecting to the middle pipe is shortest. So the jet flow oscillator with reaction cavity is proposed. Effects on the jet flow oscillating of the element's geometrical sizes and operating conditions are studied. As a conclusion, the jet flow oscillates only in a certain range of geometrical sizes and operating conditions. The jet flow can not be stable oscillation if the geometrical sizes and operating conditions are not appropriate. There is a maximum oscillation expansion ratio of jet flow in the fixed geometrical sizes. At the same expansion ratio, the oscillation frequency of jet flow increases with the increasing inlet pressure, so does the size range of oscillation.(3) Effects on the oscillation frequency and the isentropic refrigeration efficiency of jet flow are studied. Pressure amplitude in the controlling tube and oscillating tube is analyzed. As a conclusion, the oscillation frequency of jet flow decreases with the increasing length of controlling tube and increases with the increasing expansion ratio, but the trend increases slowly. Pressure amplitude in the controlling tube and the oscillating tube increases with the increasing expansion ratio. Therefore the isentropic refrigeration efficiency of gas wave refrigerator increases gradually. Pressure amplitude in the middle oscillating tube is smaller than that in other oscillating tubes. The pressure wave intensity in the middle oscillating tube is larger while the reaction cavity added to the jet flow oscillator, but there is a certain gap comparing with pressure wave intensity in other oscillating tubes.