Effect of the Seal Force on Nonlinear Dynamics and Stability of the Rotor-bearing-seal System

Abstract

Effect of the seal force on nonlinear dynamics and stability of the rotor-bearing-seal system are investigated both theoretically and experimentally. An experimental rotor-bearing-seal device is designed and corresponding tests are carried out. The experimental rotor system is simplified as the Jeffcott rotor. The nonlinear oil-film forces from the journal bearing are got under the short bearing theory. The nonlinear seal forces from the labyrinth seal are got under the Muszynska's seal force model. Through numerical calculation, the rotor rotating speed, the input-output air pressure difference and the seal clearance are used as control parameters to investigate the effect of the seal force with the help of bifurcation diagrams, waterfall plots, Poincaré maps, spectrum plots and rotor orbits. Various nonlinear phenomena and stability of the system are found and discussed. Theoretical results from numerical analysis are in good agreement with results from experiments. Conclusions are drawn and prove that this study will contribute to the further understanding of the effect of seal forces on nonlinear dynamics and stability of the rotor-bearing-seal system.