Impacts Of Structural And Operating Parameters On Performance Of Gas Wave Ejector

Gas wave ejector is a type of pressurization device achieving energy transfer between high and low pressure fluids by pressure wave propagation. It has several advantages, such as simple structure, low energy consumption, workable operation with fluid and high isentropic efficiency, therefore gas wave ejector is important and promising in the natural gas extraction and gathering system. The research on gas wave ejector can help improve its performance in order to realize the application in natural gas industry.Limited work has been reported on the research of gas wave ejector. In this paper, the impacts of structural and operating parameters on performance are studied by means of numerical simulation and experimental research. Besides, based on the theory of one-dimensional analysis and numerical optimization, a static ejector is designed, and the performance of the two ejectors is compared. The main results include:(1) The two-dimensional numerical model was established, and the impacts of clapboard thickness and channel width on performance were studied. A single channel numerical model was established to investigate the propagation speed of shock wave at different expansion ratios when the media were air and methane, respectively. According to the matching relationship between port width and wave movement, the port width and position were obtained when the medium was methane.(2) A test rig of gas wave ejector was set up. The experimental research about impacts of rotation speed and deflection distance on vacuum degree at low pressure port was conducted when entrainment ratio was zero, and the performance map was also obtained. The influence of the channel width was discussed and the experimental result showed that isentropic efficiency raised by6%when the channel width increased from8mm to12mm. The research about gradual open process of the channel indicated that the gradual open loss reduced as relatively opening time decreased and flow loss reduced as the channel width became larger. The loss was minimal when the channel width was12mm, which agreed well with the experimental results.(3) One-dimensional analysis and optimization analysis of static ejector were successively carried out, and main structural parameters at different mixing pressures were gained. An experimental prototype with adjustable and convertible features was designed and manufactured. The experimental study about impacts of mixing pressure and high-pressure nozzle distance on the performance was implemented. Gas wave ejector and static ejector were compared using experimental results in the same condition and the results showed that the performance of gas wave ejector was superior to static ejector when the expansion ratio was1.5. The reason of excellent performance of gas wave ejector was analyzed in theory.