| With the development and update of new aero-engines technologies,circumferential seal ring used in main bearing cavity is needed to accommodate higher requirements,the sealing material and structure are needed to fit high friction velocity and high temperature,and the seal structure is required to have work performance of large radial runout and deflection angles.In this paper,the circumferential seal characteristics are studied considering the condition of large deflection angle.Based on in-service circumferential seal structure and performance requirements of circumferential seal in geared turbofan engine,finite element method is used to analyze the structural analysis,thermal structural coupling analysis under different deflection angles,the following characteristic and leakage amount of graphite circumferential seal under different deflection angles,radial jump and the comprehensive effect of them are analyzed.The main contents of this paper are as follows:(1)The force analysis and calculation formulas of circumferential sealing ring are completed under the angular deflection conditions,mainly includes:circumferential seal force analysis,calculation of friction heat,radial contact loads and axial contact loads.According to the actual working condition of circumferential seal,the center line of the seal ring is taken as the reference line,and the center line of the seal ring and the reference line are deflected by an angle,and the 3D model is built.(2)Using finite element method,based on the different assembly with different deflection angles,structural analysis,thermal-structural analysis is carried out.The stress distribution and deformation distribution characteristics of the main and auxiliary sealing surface of the sealing ring and the variation law of the stress and deformation with the deflection angles are determined.It shows that the thermal structural analysis results of maximum stress and maximum deformation of main and auxiliary sealing surface are greater than that of structural analysis,the positon of maximum stress has changed,temperature has a significant effect on circumferential seal,thermal structural coupling analysis is necessary.(3)Based on the work requirements of radial run-out and angular deflection in circumferential seal,the displacement excitation is used to carry out the dynamic analysis under the conditions of radial runout,angular deflection and comprehensive action,nine nodes are respectively chose along the circumferential direction in the main and auxiliary sealing surface uniformly,the nodes displacement responses are obtained under different radial runout,different deflection angles and are compared with the results of nodes in runway and seal seat,following characteristics are different in different position of sealing surface,the central region is relatively better,angular deflection affects more on main surface,radial runout affects more on auxiliary sealing surface,the change rule of following characteristics on main seal surface and auxiliary seal surface are obtained.(4)According to the results of the dynamic analysis,for a period of motion,the leakage clearances and its rules of the sealing interface with deflection,diameter jump and the combined action of the two are obtained by calculating in the way of summing and averaging the displacement differences,and the calculation formulas of the leakage amount of the sealing clearance are given,and obtained that deflection angle effect more on main seal surface,radial jump effect more on auxiliary seal surface,and the leakage amount change rules of the main sealing interface and the auxiliary sealing interface are obtained.The research results of this paper provide a good foundation for the improvement of circumferential seal performance and design. |
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