Models of the rotor-seal system for hydraulic turbine and its nonlinear dynamics analysis

With comparison analysis of several models of the fluid exciting force for the clearance of the hydraulic turbines, this paper describes the main characteristics of the fluid exciting force by the Muszynska model. The nonlinear Jeffcott model of the rotor-seal system for the clearance of the hydraulic turbines has been established. The influence of the main parameters on the stability of the system and the characteristic of whirl amplitude are studied with rotation speed of the rotor by the numerical calculation. The results state that when the rotation speed of the rotor reaches the threshold speed, the whirl amplitude of the system begins to appear. With the rapid rotation speed, the amplitude of vibration increases, and the rotor-stator rubs will be happened to destroy the system. So studying on the fluid excitation of the hydraulic turbine rotor-seal system is important and meaningful.