Nonlinear dynamic analysis of a rotor system excited by labyrinth seal force

Here, the nonlinear dynamic model of a labyrinth seal-rotor system was built using Muszynska's nonlinear seal forces. In the process of nonlinear dynamic analysis, the axial mean flow velocity of the labyrinth seal was determined with the two-control-volume model. Applying Runge-Kutta-Fehlbrg numerical integration, the nonlinear dynamic equation of the system was solved. The effects of parameters, such as, labyrinth seal clearance, seal-radius, number of seal strips, cavity-width and inlet air pressure on leakage and axial mean flow velocity were analyzed. The influences of rotational speed, inlet air pressure, eccentricity and effective seal-length on the nonlinear dynamic characteristics of the system were also studied. The nonlinear dynamic properties of the system were described with bifurcation diagrams, axis orbits, Poincare Maps and frequency spectra. The numerical results showed that the changing of rotating speed, seal geometry and seal medium parameters can induce abundant nonlinear dynamical behaviors like periodic motion and quasi-periodic motion, etc.