Research On Cavitation Vibration And Noise Of Conical Throttle Valve

Throttle valve is the most widely used core control component of hydraulic system,which plays a key role in the performance of hydraulic system.However,there is usually cavitation at the orifice of the throttle,and the vibration and noise caused by cavitation are very serious.The sound pressure level of the cavitation noise is relatively high,and the impact on the environment and human can not be ignored.Cavitation vibration will affect the stable operation of the system,and even damage to the hydraulic components in the system.At present,the research on cavitation is not very thorough,and it is limited to the complex flow path and flow state of the hydraulic throttle valve.Therefore,it is very important to study the vibration and noise of hydraulic throttle.In order to solve the problem of vibration and noise caused by cavitation of hydraulic throttle valve in hydraulic system,the method of combining theoretical analysis with experimental analysis is studied.In this paper,the multi-channel vibration and noise of LMS company are used to analyze the cavitation signal.Acquisition of cavitation vibration signal by using acceleration sensor and signal acquisition of cavitation noise by microphone pressure sensor.Acquisition of cavitation vibration and noise signal and the high speed camera to obtain the image information of the cavitation shape of the throttle valve.The results show that the vibration intensity of the vibration signal and the magnitude of the sound pressure level increase when the throttle valve is cavitation.The characteristics of the cavitation signal under different inlet pressure,outlet pressure and opening are studied.The variation trend of cavitation vibration and noise sound pressure level is obtained.Because the human ear heard audible frequency is 20-20000 Hz,the noise in the frequency range of the human ear is the worst.Therefore,this paper studies the cavitation vibration and noise signal in the frequency below 20000 Hz.It is found that the frequency of cavitation vibration and noise signal is above 5000 Hz.The vibration frequency of traveling cavitation in the throttle valve is tested in the 7500-10000 Hz frequency range.And there is a certain frequency shift phenomenon.The frequency of fixed cavitation is in the range of 10000-15000 Hz.With the increase of inlet pressure,the cavitation intensity increases,the cavitation vibration and noise level increase strong.With the increase of back pressure,the cavitation intensity decreases.The cavitation intensity increases first and then decreases as the opening increasing.One-stage throttle valve causes more severe cavitation than two-stage throttle valve and cavitation region is also greater.The cone angle of the valve core has a great influence on the cavitation.In the two-stage throttle valve seat,the angle of the cone angle of 90 degree valve is more severe than that of the cone angle of the valve core of 60 degrees.