New high precision direct integration scheme for nonlinear rotor-seal system

In this paper, the mechanical model of labyrinth seal rotor system with Muszynska seal forces is established. A new efficient and high precision direct integration scheme is proposed based on 2N type algorithm for the computing of exponential matrix. According to the proposed model and numerical integration method, the response of the unbalanced rotor-seal system is investigated. Combining precise integration method with Poincare mapping method, the bifurcation diagrams associated with various rotor speeds are presented and the course of the system shifting from the steady state to the unsteady state is analyzed. The study demonstrates that precise integration method can be effectively applied to nonlinear numerical analysis of rotor-seal system. The scheme is significantly less sensitive to the size of time step compared with other existing methods, so a large time step may be used and the computing time reduced substantially.