Computational Analysis of Sealing and Stability of a Deformable Floating and Fixed Rings of an Annular Seal

Abstract

Solving the hydroelastic problem by using Ansys System Coupling (Mechanical and CFX) for floating and fixed rings of a deformable annular seal made it possible to analyze the influence of the cylindrical shell thickness, the inlet and outlet edge dimensions, inlet pressure, and shaft radial displacement on the hydrostatic pressure distribution and the clearance value on length, leakages, stress-strain state, and radial force. The analysis of static stability at an inlet pressure of 10 MPa for the basic seal design showed that the static radial force in the range of radial movements of the shaft from 0 to 50% of the clearance is centering, even though the inlet part of the seal clearance has a confusor, and the outlet part has diffuser form. However, the dynamic coefficients of the fixed sealing ring have a negative value of direct stiffness but positive values of direct and cross-coupled damping and cross-coupled stiffness. Verifying computational 2D and 3D models with experimental results from the literature showed that the maximum relative error does not exceed 10.7% for the hydrostatic pressure, 18% for the clearance, and 8.6% for the leakage value. Simultaneously, according to the trend, all calculated dependencies are identical to the experimental results.

Keywords

• deformable annular seal
• clearance
• hydroelastic problem
• sealing
• stability