双吸离心泵正反转工况流致振动噪声研究

摘要

In order to better understand the law of vibration and noise of a double-suction centrifugal pump,a double-usction centrifugal pump was taken as a study object.Based on the indirect boundary element method,(IBEM),a LMS Virtual-Lab computational platform was adopted to compute the forced vibration response of the pump due to flow based on modes of the pump shell.Then the forced vibration equations and the IBEM acoustic wave equations were used to form the coupled equations,these coupled equations were solved to obtain the distribution of sound pressure level and the direction distribution of sound pressure level of the double-suction centrifugal pump outside radiation sound field under the hydraulic turbine working condition and the pump working condition.The results showed that the dipole sound source is the main sound source of fluid-induced noise;the volute tongue unsteady pressure fluctuation is the main noise source;the blade frequency and its frequency multiplication are the main induced frequencies;the pump shell's resonances appear;so,the acoustic-vibro interaction can not be neglected.The study results revealed the sound-vibration interaction law for the outside radiation sound field of a double-suction centrifugal pump under hydraulic turbine working condition and the pump working condition,and provided a theoretical basis for further study.%为深入了解双吸离心泵运行的振动噪声规律,以某一双吸式离心泵为研究对象,基于声学间接边界元法(IBEM),采用LMS Virtual-Lab分析计算平台,进行基于泵壳模态的强迫振动响应计算.然后根据泵壳模态强迫振动响应计算与声学间接边界元的声学波动方程求解耦合方程,得到双吸泵在液力透平工况和泵工况下外辐射声场的声压级指向分布和声压级分布.结果表明:偶极子声源是流体噪声的主要声源;在蜗壳隔舌处非定常脉动力是主要的噪声源;叶频及其倍频是双吸泵外辐射声场噪声的主要诱导频率;泵壳发生了共振,所以声振耦合的作用不可忽略.研究揭示了双吸泵作液力透平及泵工况内部流动诱发的外辐射声场的声振耦合计算规律,为后续减振降噪研究提供了理论基础.