Computational Analysis of Nonlinear Dynamics of a Multi-disk Rotor-Bearing-Brush Seal System

The seal force and oil-film force are two of the main factors which would cause the instability of rotor system, so it is important to further study the nonlinear dynamic characteristics of the multi-disk rotor-bearing-seal system. In order to establish the multi-disk rotor-bearing-brush seal system model of a gas turbine, the seal force model of brush seal and the nonlinear oil-film force model based on short bearing theory were adopted considering the lateral deflection of the disks. The equation of motion was solved by time simulation using the fourth order Runge-Kutta method. The influences of key parameters including rotor speed and eccentricity phase-difference on the vibration response and dynamic behavior of multi-disk rotor-bearing-brush seal system were discussed. The result showed that the system became more stable when the eccentricity phase-difference decreased.