Numerical calculation of dynamic coefficients for gas film cylinder seal

Aiming at the dynamic analysis of gas film cylinder seal, the dynamic pressure differential equations of gas film are established by means of the linear perturbation method. A calculation method of dynamic stiffness and dynamic damping coefficients of a gas cylinder seal suffering small perturbations under two degrees of freedom is presented. The finite element analysis model of eight dynamic coefficients of gas film cylinder seal is established and the finite element numerical calculation process and method is presented. The model and the numerical method are proved to be correct through the computational example and a parametric study is performed to gauge the influence of the compressibility number and the average thickness of gas film to the dynamic coefficients. For downstream spiral-grooved gas film cylinder seal, the dynamic coefficients are obtained and the characteristic curves of the coefficients under different conditions are plotted. The direct stiffness and damping coefficients present a more complex variation, while the cross-coupled stiffness and damping coefficients are axisymmetric. The calculated results of the dynamic coefficients are helpful to the stability analysis of a gas cylinder seal and a guidance is provided for the design of the gas cylinder seal.