Study Vibration Performance Of Rotor System Based On Torsional Excitation

As the turbine-generator unit and other large equipment are increasingly sophisticated and more complex. Large torque is acted on shafts repeatedly. Under the excitation of torque frequently, the vibration of rotor system will appear new features. So, researching the vibration characteristics the rotor system under excitation, which is important to improve accuracy of fault diagnosis and stability of the rotor system.Considering the nonlinear oil film force and the influence upon the rotor system of elastic supporting system, a mathematical model of rotor system under torque excitation is established, and the impact factor of torque’s influence upon the load is brought in. The nonlinear behaviour of the system is studied by using Rounge-kutta method, simulations and testing are conducted respectively under the condition of linear torque incentive and no torque incentive. Correctness is proved by comparing value of simulation and measured.The dynamic model of three-span rotor system is established by ignoring torsional vibration and the impact factor of torque’s influence upon the load is brought in. The bending vibration of rotors is researched by numerical analysis and experimental research. Respond of bending vibration is studied when the rotor system is subject to torque excitation which is linear torque of different slope and transient torque of different amplitude. With the work of linear torque excitation, the bigger displacement of vibration curve offset the equilibrium position, the trend of displacement change in the wheel center is also linear, axis orbit of the rotor system is divergent. With the work of transient torque excitation, the greater amplitude, the bigger displacement of vibration cure offset the equilibrium position, the displacement in the wheel center also changes transiently, axis orbit of the rotor system is concentrated.The feature of the vibration signal of the rotor system under different character of torque excitation was extracted by using the analysis of time domain, frequency domain and wavelet packet, which provides a basis for the identification of different torque excitation. Finally different torque excitation and the vibration performance was simulated by experiment, the bearing load on different supporting position, vibration characteristics and axis orbit trajectories were got, and the numerical simulation result was verified by the result of experiments.