Vibration Source Analysis And Vibration Control Of Vertical Multistage Centrifugal Pump Set

The low-noise design is the basic way to control the vibration of the electromechanicalequipment, with vibration source analysis and vibration response prediction as its key issue.So it is significant for the rotating machinery, one of the most common electromechanicalequipment, to improve the low-noise design level.In this thesis, for the multistage centrifugal pump set with serious vibration used incollege teaching laboratory, vibration source analysis and vibration control are realized basedon the load identification. The main research contents are as follows:1. The modal characteristics of the rotor, stator and supporting components are analyzedprimarily. Then the reasons of the vibration response are analyzed preliminarily. It is foundthat the subsystem exists modal resonance in different frequency bands.2. The FE model of the set is built whose accuracy is verified by the experimental model.The condition number is calculated and the measure points of vibration response used in theidentification are chose. All kinds of sources are equivalent to the bearing point loads which isidentified with the inverse of frequency response function method. Based on the identificationresults, the reasons of the vibration response are analyzed again. It has been found that thevibration source in the middle band has a large amplitude.3. The three-dimensional steady numerical calculation of the flow field of the wholepump is made in design conditions. The distribution rule of the static and dynamic pressure,velocity, and trace in the middle-section of each stage is obtained. This reveals the major flowcharacteristics of the pump. Then the three-dimensional unsteady numerical calculation isperformed in the same condition. The pressure pulsation characteristics of the impellers andthe tongue area are obtained, revealing the important unsteady characteristics. Besides, thefrequency and amplitude of the motor electromagnetic excitation are calculated. The analysisresults of the vibration source characteristics indicate that fluid excitation is continuousspectrum in low and middle frequency band and the electromagnetic excitation is continuousspectrum in middle frequency band.4. Based on the above analysis, the reasons of the vibration response are analyzed indetail and the control strategies are proposed. Then the experimental verifications for thestructure and source optimization are carried on. The vibration acceleration of the improved pump set reduces to35%of the original pump set.In the thesis, the improved design flow of the electromechanical equipment with seriousvibration is summarized preliminarily by modal analysis, load identification, vibration sourceanalysis and vibration control. The work provides a useful reference for low-noise design ofthe electromechanical equipment.