A Study on Nonlinear Dynamic Stability of Labyrinth Seal-Rotating wheel System in Hydraulic Turbines

The Muszynska's model of seal fluid dynamic forces is used in this paper to analyze the nonlinear dynamic characteristics of labyrinth seal-rotating wheel system in hydraulic turbines and investigate the influence of labyrinth seal on nonlinear dynamic stability of hydraulic turbines. The results show that the Hopf bifurcation will occur and the rotating wheel will come into bifurcated periodic orbit after the rotor speed exceed its threshold, and the amplitude of bifurcated motion increasing with the rotor speed. At a certain speed, the rotating wheel will impact the seal. Finally, the influence of physical and structural parameter of seal on rotor is investigated. Sensitivity analysis of nonlinear dynamic characteristics is performed by changing the physical and structural parameters of seal-rotating wheel system