Dynamic Behavior of a Rotor-Bearing System with Integral Squeeze Film Damper and Coupling Misalignment

Rotor-bearing system is the core structure of turbomachinery, transmission trains and other rotating machinery. Its dynamic characteristics directly influence the performances and the safety operation of the whole system. In most situations of practical engineering, the rotor-bearing system is required to work under a low vibration mode for high rotation accuracy. It is an extreme case that rolling element bearings are facilitated for the support of high speed turbine rotors. Squeeze film damper has its capability of damping the vibration energy transmitted between the rotor shaft and the bearing pedestal. Its integral version, the integral squeeze film damper (ISFD), has the advantages of small volume, low mass and simple structure, which are well suited for the stable running of high-speed rotor-bearing structure. Considering the elastic support of both ends of the rotor shaft, misalignment generally exists between the rotor axis and the central connection of two support bearings. Thus, in this paper, the dynamic characteristics of a rotor-bearing system with ISFD are studied based on the established 9-DOFs model. Misalignment and the unbalanced mass are considered in the model to evaluate the system performances under such excitations. It is concluded that the ISFD supported system is more stable than the ball bearing supported structure. Besides, the ISFD is capable of suppressing the vibration energy induced by coupling misalignment with some pre-designed damper parameters.