Study On Mechanical Vibration Characteristics Of Energy Recovery Pump-Motor Integrated System

With the development of economy and the progress of society,energy consumption is increasing day by day.Energy recovery devices are widely used in residual pressure energy recovery of reverse osmosis desalination and synthetic ammonia industry,power recovery of pump motor test system,secondary regulation hydraulic system(hydraulic transformer)and other fields.At present,most of the core technologies are monopolized by foreign countries,and independent research and development is particularly urgent.An innovative energy recovery pump-motor integrated device is proposed for energy recovery system.The high-pressure and high-speed working conditions make it one of the vibration sources of hydraulic system.When resonance occurs,its life cycle will be sharply reduced.At the same time,it is essential for the stability and reliability of the whole system to study the distribution of its vibration characteristics.Therefore,the mechanical vibration characteristics of the axial piston pump-motor are studied by using the eccentricity and unbalance of the rotor system as a single exciting source,which is of great significance to the structural optimization of the device and the vibration and noise reduction of the system.The energy recovery principle of pump-motor integrated device is briefly described.The vibration mechanism is further analyzed and its vibration description is given.According to the analysis of vibration transmission path,five vibration transmission paths are found and the final recipients are all shell surfaces.Subsequently,a simplified dynamic model of the pump-motor integrated device is established,including the establishment of the mathematical model of the transmission path of the vibration system.The stiffness and damping parameters of the mathematical model are determined preliminarily by means of simulation analysis and reference.Then the dynamic model of the vibration system is solved by using Runge-Kutta method through MATLAB programming.The time/frequency domain characteristic curves of the vibration acceleration of the front,middle and rear shells of the vibration system are obtained.An analysis platform is built in ANSYS Workbench.The natural frequencies and modes of the pump-motor structure are obtained by modal analysis,and the position of the lower stiffness of the shell surface structure is found.Then the sensitivity areas of the structure in the three dimensions of X,Y and Z are found by response spectrum analysis,and the response in the Z dimension is the most sensitive.According to the harmonic response analysis in these areas,it is found that the resonant peak frequency is close to the fifth natural frequency of the structure.The vibration characteristics of the shell structure under the resonant frequency and its variation law are further studied.On the basis of theoretical analysis,a test platform for energy recovery of pump-motor is built.Vibration test of pump-motor integrated system is carried out by using Donghua dynamic analysis and measurement instrument,and vibration evaluation is further given by using the vibration intensity index.The analysis results show the vibration characteristics of the new pump-motor integrated energy recovery device.The research results have good engineering application value and lay a foundation for further structural optimization.The methods and ideas of vibration characteristics analysis and evaluation embodied in this study can also provide specific reference for similar structural vibration evaluation,help to predict structural vibration characteristics,optimize structural design,expect to bring certain social and economic benefits,and also play a vital role in energy recovery,protection and sustainable development.