The Nonlinear Dynamic Research Of Bulb Turbine Generator Shafting

Hydroelectric system is a complex nonlinear dynamic hydro-mechanical -electrical system. As the system is running, the rotor shows a complicated non-linear dynamic characteristic, especially under the effects of unbalanced magnetic pull and rub-impact. The rotor showed more complicated dynamic characteristics, whereas that is much closer with the condition of real vibrations of rotor.In this paper, the rotor model with two-disc was established according to the real rotor axis orbit. Considering the gravity and damping, the coupled bending and torsional vibrations dynamic differential equations of imbalance rotor was concluded. Through the numerical simulation, the coupled bending and torsional vibrations characteristic diagram of rotor under running rotating speed was obtained and analyzed. Furthermore, with the rotating speed and mass eccentricity as the bifurcation characteristic parameters, the bifurcation characteristics of rotor were studied. From this study, rotating speed and mass eccentricity were found to play important roles in the coupled bending and torsional vibrations of the rotor system.In order to investigate the dynamic characteristics of rotor system under the effects of unbalanced magnetic pull, the coupled bending and torsional vibrations rotor model with two-disc under the effects of unbalanced magnetic pull was established. Through the numerical simulation, several diagrams of rotor under the running condition were obtained, such as spectrum graph, Poincare graph and so on. From the analysis of those graphs, the results as follow were obtained:the condition showed more complicated non-linear dynamic characteristics; varies non-linear phenomena compressing periodic, quasi-periodic motions occurs at different rotating speed. From this study, eccentricity was found to play an important role in the coupled bending and torsional vibrations of rotor.In the last part, a based on model of a rigid rotor system under axial thrust with rotor-to-stator is developed based on the classic impact theory and analyzed by the Lagrangian dynamics. The effects of friction coefficient and the stator stiffness are researched. With the changes of these parameters, the changes of vibration characteristics of rotor system turn to be very complicated, and the periodic motion, complicated quasi-periodic motion, or chaotic motion may occur in the response of the rotor system.