Study Of The Oscillation And Refrigeration In A Static Gas Wave Refrigerator

Energy source and environmental problem are becoming more and more important for the whole society, and the gas wave refrigerator has been the focus for the effective use of the pressure energy. The static gas wave refrigerator can separate the gas into hot and cold part by the motion of the shock wave and expanding wave in an oscillator using the pressure energy of the gas. 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. In this paper, the two-tube static gas wave refrigerator generated by a sonic oscillator and a feedback oscillator is studied. Pressure gas is converted into oscillating gas and injected into the receiving tube by using a sonic oscillator and a feedback oscillator. The work and conclusion of this study are as follows:1. The supersonic oscillation process and principle in the sonic oscillator and feedback oscillator are studied. A two dimension computational model is applied to simulate the attatchment, switch, oscillation and pressure wave in the sonic oscillator and feedback oscillator. The jet flow oscillates as a "square wave" in a sonic oscillator and "sine wave" in a feedback oscillator. As the jet flow is attaching to the wall, there is expanding wave and compressing wave in the jet flow zone. During the oscillation, both the pressure wave and the gas momentum act on the switch of the jet flow. The pressure difference between the controlling ports is also periodic as the jet flow oscillates, and the time the pressure difference acts on the gas in the controlling pipe determines the velocity of the gas. At the same time, the viscosity of the gas affects the period of the oscillation.The oscillation and flow in the oscillator is analyzed under different parameters of nozzle, splinter distance, outlet tunnel and so on. If the splinter distance is reduced, the gas involved into the oscillator also decreases, and so the energy loss can be reduced, so the outlet pressure recovery increases. Minimizing the length of the outlet tunnel can also be helpful for increasing the pressure recovery. At the same time, potential difference, the width of the outlet tunnel, degree of the splinter, shape of the splinter and so on can also contribute to the pressure recovery, and general consideration should be taken in designing and applications.2. The gas and wave's motion and propagation in the receiving tube are studied. Fresh gas in the receiving tube can only move for a short distance, and the contact face accelerates at first, then keeps for a while, and then exhausts rapidly. The wave moves in a certain speed and under different pressure ratio, the speed also varies. As the wave sweeps, the pressure, density and temperature of the gas rise rapidly. There is obvious reflection as the wave arrives at the close end of the straight long pipe. Different types of wave absorber are studied. The structure of shrink-expand in the close end can absorb the reflected wave. For the different oscillation of the jet flow and the different structure of the receiving tube, the pressure wave in the receiving tube is also different. So the phase can be adjusted by using the shrink-expand wave absorber. The average pressure of high frequency generated by a feedback oscillator is periodic.3. By the experimental study of the two-tube static gas wave refrigerator generated by a sonic oscillator and a feedback oscillator, influence of operating parameters and structure parameters is analyzed. Matching the other parameters, as the inlet pressure rises, the temperature drop also rises. The temperature drop also rises as the inlet temperature rises. Matching with the oscillation frequency, the length of the receiving tube, diameter of the nozzle and the pressure ratio, there is a best injecting frequency. The gap between the oscillator and the receiving tube also influents the refrigeration. There is also a best exhausting gap. If the gas is gernated by a high frequency oscillator- a feedback oscillator, as the frequency to drive the gas in the receiving tube is also high, so higher temperature drop can be realized as to the sonic oscillator.