Influence of Squeeze Film Damper on the Rub-Impact Response of a Dual-Rotor Model

PurposeThe main objective of this paper is to investigate the influence of a squeeze film damper (SFD) on the dynamic characteristics of a dual-rotor model experiencing rub-impact.MethodsIn the context of an aero-engine, the dual-rotor system is typically mounted on nonlinear supports, including rolling contact bearings, squirrel-cage elastic support, and squeeze film dampers. Despite its intended purpose of vibration reduction, the squeeze film damper affects the nonlinear dynamics of the system. To explore this, we construct a dynamic model of the dual-rotor system using one-dimensional finite elements. In this model, the high-pressure rotor comprises a compressor and a turbine, while the low-pressure rotor includes a fan in addition to a compressor and a turbine. Both rotors are supported on bearings, with the bearing near the fan disk mounted inside a squeeze film damper. The equation of motion for the squeeze film damper is derived using Reynolds's equation based on the short-bearing approximation. Results are obtained through numerical integration techniques and analyzed using frequency response, FFT spectrum, and Poincar & eacute; maps.Results and DiscussionsBased on the study, it is observed that an SFD with appropriate parameters can reduce the speed range of rub-impact, swiftly transitioning it to the no-rub region, indicating an early onset of saddle-node bifurcation. Additionally, the squeeze film damper can suppress asynchronous vibrations in the model that may arise due to the chosen set of system parameters.