Study on gas flow-induced vibration for a three-dimensional rotor-seal system

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. 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 a frequency component of rotor first-order critical speed. The amplitude of the component will increase with the increase of 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 are obtained.