Abstract: Based on the circumferential sealing analysis of deflection angles， the force model and the finite element analysis model were established. Through structural analysis and thermo-structural coupling analysis， the distribution of stress and deformation of the main and auxiliary sealing surfaces were obtained under different deflection angles， as well as the variation law of leakage gap and leakage amount. The stress and deformation of the main and auxiliary sealing surfaces are evenly distributed. The maximum stress and maximum deformation are located at the tongue. The maximum deformation of the main sealing surface is larger than that of the auxiliary sealing surface. The maximum stress and maximum deformation increase with the increasing of deflection angles. The thermal-structural coupling analysis stress and deformation are basically consistent with the structural analysis distribution， but they are larger than that in the structural analysis. The gap of the main sealing surface increases from the bearing chamber to the air chamber， and the gap of the auxiliary sealing surface increases from the center to both ends， and the gap at the joint is the largest. The amount of leakage increases with the increasing of deflection angles.

Key words: deflection angle, circumference sealing, structural analysis, thermal-structural coupling analysis, leakage