Side clearance effects on squeeze film damper performance

Computational fluid dynamics has been used to study the influence of end seal clearance and flow path length on the performance of a circular orbiting squeeze film damper with a central circumferential feed groove. Results indicate that to be effective in modifying the damper stiffness and damping characteristics, the axial clearance between the damper and the seal needs to be of the same order of magnitude as the radial clearance of the damper in its housing. The pressure distribution is predicted to remain close to a π-film, regardless of seal clearances, and oil flow patterns are also given. It is concluded that over a narrow range of axial seal clearances, the damper performance is very sensitive to the axial seal clearances; and that over this range, the vibration behaviour of squeeze film damped rotor-bearing systems incorporating such axial seals will be significantly influenced by machining and assembly tolerances.