Transient change of the operating parameters has a serious influence on the stability of liquid film seals. Three-dimensional model of sealing clearance was established based on Matlab. Reynolds equation considering JFO cavitation boundary was discretized by finite difference method. SOR iteration was used to solve fluid film pressure distribution. By further solved coupled Reynolds equation and transient dynamic equations

the influence of continuous change of working conditions and pressure disturbance on transient characteristics were analyzed. The results show that squeeze effect of liquid film during transient change of pressure has more significant influence on sealing performance than speed change. The faster approach speed of seal face

the higher carrying capacity of liquid film extrusion and the greater the velocity of the discharge of the end face fluid. Instantaneous change of pressure easily leads to the axial velocity oscillation of stator ring. The greater the pressure difference

the greater shock amplitude. Leakage rate and cavitation ratio has a large disturbance tends to be stable after abrupt mutation in the case of differential pressure disturbance. Pressure rise compared to pressure drop is more easily to restore stable state. Friction torque varies smoothly during the condition changing without significant fluctuation.