In order to investigate the effect mechanism of taperclearance on air flow force of pocket damping seal,a numerical solution model of taperclearance pocket damping seal was established to study the effect of import/export pressure ratios,eccentricity ratios,rotational speeds and taper degrees on the air flow force of pocket damping seal.The sealed air flow test bench was designed to analyze the size of air flow force of the taperclearance pocket damping seal at different inlet/outlet pressure ratios and eccentricity ratios.The effect mechanism of taperclearance on pocket damping sealing air flow force was revealed by sealing circumferential pressure distribution law.The results show that with the increase of the inlet/outlet pressure ratio and the eccentricity,the fluid dynamic pressure effect is enhanced in the sealing peripheral wedge clearance,the radial air flow force of the convergenttapered clearance pocket damping seal and the continue clearance pocket damping seal is increased,the absolute value of the divergenttapered clearance pocket damping seal is increased.When the speed is 0,the sealing tangential airflow force is 0.With the increase of rotational speed,the tangent air force of the seal gradually is increased,and the circumferential flow of air flow in the sealing clearance is the main reason for the formation of the tangent air flow force.The radial clearance of convergenttapered clearance pocket damping seal along the flow direction of the air flow is constantly decreasing,the concentration of gas increases the pressure in the seal chamber and increases the radial pressure difference,thus producing a large radial airflow force.