Sealing effect on the performance of squeeze film damper

Seals used in the squeeze film damper restrict the side leakage of the lubricant, thus providing a measure of additional damping. In this paper, the serrated piston ring and end-plate seals are studied numerically using CFD-ACE+, a commercially available finite volume based algorithm. Research shows that the damping coefficients for the piston ring seal decrease in magnitude with the increase in the number of axial grooves in the circumferential direction until they reach a fairly constant value. However, the pressure distribution and hence the hydrodynamic forces are strongly affected by the number and geometry of the axial grooves. The damping coefficients for the end plate seal increase in magnitude rapidly with the decrease of the seal clearance below the clearance of the damper, but increase slowly when the seal clearance is larger than that of the damper. The direct inertia coefficient increases with the decrease in the seal clearance but the magnitude of cross-coupled inertia coefficients increases with the decrease in the seal clearance, and then falls down towards the values for the infinitely long bearing assumption. Both the damping and inertia coefficients increase with the increase in seal length.