A NEW HIGH PRECISION DIRECT INTEGRATION SCHEME FOR NONLINEAR ROTOR-SEAL SYSTEM

摘要

In this paper, the nonlinear mechanics model of rotor-seal system is established with Muszynsca seal forces. A new, efficient and high precision direct integration scheme is proposed based on the 2~N type algorithm for the computing of exponential matrix. The proposed model and numerical integration method are employed to investigate the nonlinear phenomena in the unbalanced rotor-seal systems, To study the influence of the seal to the nonlinear characteristics of the rotor system, 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 the proposed high precision direct 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. A larger time step may be used and computing time substantially reduced.