| The gas wave ejector is an ejection and supercharging device that utilizes pressure waves formed by direct contact between high and low pressure compressible fluids to achieve efficient energy transfer.With the advantages of simple structure,low rotation speed,high energy transmission efficiency and large liquid holding capacity,it has broad application prospects in the fields of natural gas formation pressure comprehensive utilization with multi-gas combined mining technology and industrial waste energy recovery.In this paper,the flow characteristics and the influence of various parameters on the performance of the gas wave ejector are studied by numerical simulation and experimental methods.For the problem of dynamic pressure loss during medium pressure gas exhausting process,steady flow structure and diffusion structure are proposed.The main work and conclusions of this paper are as follows:(1)The ideal wave diagram of gas wave ejecting process is constructed,and the formation and propagation characteristics of various pressure waves and the flow characteristics of each port are analyzed.(2)Two-dimensional and three-dimensional periodic numerical calculation models are established.The flow characteristics of ejecting process is analyzed,the motion laws of the interface between high and low pressure gas,the variation laws of the length and pressure of the pressure stable zone,the influence mechanism of the gap on the ejecting process and the variation laws of the leakage mass flow rate are obtained,the influence mechanism,optimal parameters design method and its applicable range of the feedback structure are studied.(3)An experimental platform for the study of the gas wave ejector performance is established.The effects of offset distance of medium pressure port,the solid wall distance between high and low pressure ports and the inlet and outlet gap width on the ejecton performance are studied,and the optimal value selection and design method are obtained;Fixed the structural parameters of the gas wave ejector,the variation laws of the ejection performance and the mass flow rate of each inlet port are studied,after each operating parameter deviated from the design point;The effects of design rotation speed on the ejecton performance,the mass flow rate of each port and equipment throughput are studied.It is pointed out that there is an optimal value for the design rotation speed.(4)The calculation model for analyzing the energy loss during medium pressure gas exhausting process is established,and the values of its energy loss under different compression ratios is obtained.The energy loss under low compression ratio is greater than the energy increase of low-pressure gas.A flow stabilizing structure and diffusion structure are proposed to recover the dynamic pressure of the medium pressure gas,effectively reducing the energy loss of the exhausting process,and making the actual compression ratio on both sides of the wave rotor less than the compression ratio of the system during the injection process.When the expansion ratio is 1.5 and the compression ratio is 1.1,the ejecton rate can reach 138.7%,and the lift rate is 54.1%.When the expansion ratio is 2.0 and the compression ratio is 1.4,the ejecton rate is 2.03 times of the original ejecting process. |
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