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DETECTION OF CAVITATION IN CENTRIFUGAL PUMP BY VIBRATION METHODS 被引量:15
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作者 NI Yongyan YUAN Shouqi PAN Zhongyong YUAN Jianping 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2008年第5期46-49,共4页
For the purpose of detecting the cavitation of centrifugal pump onsite and real time, the vibration signals on varied operation conditions of both cavitation and non-cavitation obtained through acceleration sensors we... For the purpose of detecting the cavitation of centrifugal pump onsite and real time, the vibration signals on varied operation conditions of both cavitation and non-cavitation obtained through acceleration sensors were analyzed. When cavitation occurs, the cavities near the leading edge of the blade will appear periodic oscillating, which will induce quasi-synchronous vibration. The frequency of the quasi-synchronous vibration symmetrically appears on the two sides of the blade passing frequency, by which the cavitation incipiency can be detected. During the developing process of the cavitation, as the severe complexity of the unsteady flow, it is very difficult to detect the development of cavitation by classical analysis methods. Fractal method of Higuchi is successfully used for detecting the incipiency, fully development of cavitation and the development between them. 展开更多
关键词 Centrifugal pump cavitation Vibration Detection
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Numerical analysis of bubble dynamics in the diffuser of a jet pump under variable ambient pressure 被引量:4
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作者 龙新平 王晴晴 +4 位作者 肖龙洲 章君强 徐茂森 吴伟烽 季斌 《Journal of Hydrodynamics》 SCIE EI CSCD 2017年第3期510-519,共10页
Recent studies have shown that the collapse of cavitation bubbles in a jet pump can generate an extremely high pressure with many potential applications. The dynamics of the bubble is governed by the Rayleigh-Plesset ... Recent studies have shown that the collapse of cavitation bubbles in a jet pump can generate an extremely high pressure with many potential applications. The dynamics of the bubble is governed by the Rayleigh-Plesset equation. With the bubble dynamics equation and the heat and mass transfer model solved with the Runge-Kutta fourth order adaptive step size method, the oscillations of the bubble in the diffuser of the jet pump are assessed under varied conditions. To obtain the pressure variation along the diffuser, the Bernoulli equation and the pressure measured in experiment are coupled. The results of simulation show that a transient motion of the bubbles can be obtained in the diffuser quantitatively, to obtain the pressure and temperature shock in the bubble. Moreover, increasing the outlet pressure coefficient would result in a more intense bubble collapsing process, which can be used in the subsequent studies of the cavitation applications. The predictions are compared with experiments with good agreement. 展开更多
关键词 cavitation jet pump bubble collapse
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Dynamic interaction between clustered liquid propellant rocket engines under their asynchronous start-ups
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作者 Sergey I.Dolgopolov Olexiy D.Nikolayev Nataliia V.Khoriak 《Propulsion and Power Research》 SCIE 2021年第4期347-359,共13页
A nonlinear mathematical model of the low-frequency dynamics of the clustered multi-engine rocket propulsion system has been developed and the computations of the engine transient processes during the start-ups of the... A nonlinear mathematical model of the low-frequency dynamics of the clustered multi-engine rocket propulsion system has been developed and the computations of the engine transient processes during the start-ups of the four-engine propulsion system with a shared feed system have been made applied.Based on propulsion system start-up modeling the influence of the connectivity of engines in a cluster on the starting characteristics of individual engines is shown.In particular,an advanced nonlinear mathematical model of the pump cavitation phenomena is a distinctive feature of the mathematical model.The computation results showed that the asynchronous engines start-ups during rocket lift-off lead to severely nonlinear engine transients and clustered engine thrust misbalance.The influence of the rocket engines asynchronous start-ups on the clustered feed system transients depends on many factors,mainly on from the clustered feed system low-frequency dynamics,the magnitude of the disturbance and the phase difference between disturbances acting on different branches of the feed system.The deep lingering dips in the flow rate and pressure transients are possible due to the nonlinear dynamic interaction of the engines.In case of great pressure dips at the pump inlet(up to the pressure of saturated vapors during significant periods of start-up time)the cavitation breakdowns of the pumps of one or more engines from the cluster are possible.This can disrupt the operation of the entire propulsion system and leads to the failure of the launch vehicle mission. 展开更多
关键词 Liquid propellant rocket engine Clustered engine thrust misbalance Nonlinear mathematical model Start-up transient pump cavitation model Low-frequency processes Start-up sequence Shared feed system
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