Abstract: A numerical method is put forward, which can be used for analyzing the fluid-solid coupling function of gas flow-induced vibrations in a three-dimensional rotor seal system. First, a nonlinear fluid-solid coupling model is set up for a three-dimensional rotor seal system and then the nonlinear aerodynamic force of a seal device flow field is calculated through a direct numerical simulation method. As a result, an analytical method is brought forth, which evaluates the gas flow-induced vibration problem of a rotor seal system by taking into account the fluid-solid coupling effect.With respect to different speeds, pressure ratios and pre-rotations there are different amplitudes for each individual frequency component of a rotor vibration. However, there is always a frequency component of rotor first-order critical speed. Furthermore, the amplitude of the component will increase with the increase in speed, gas-flow inlet pressure and the positive-direction incoming gas pre-rotation. The above circumstance is found to be in fairly good agreement with the phenomenon of seal gas flow-induced vibrations found in engineering practice and test results.The nonlinear characteristics of the seal gas flow-induced vibrations is captured.

Key words: Fluid-solid coupling, Gas flow-induced vibration, Nonlinear, Seal