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

The 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.

In 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 Poincaré maps.

Based 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.