Dynamic analysis for the energy storage flywheel system

A subcritical or supercritical rotor is often employed to improve the energy storage efficiency of flywheel systems. Consequently, it is necessary to introduce Squeeze film dampers (SFD) in the rotor-bearing system to suppress the lateral vibration of the rotor. Although the dynamic behavior of the rotor-bearing system can be investigated in a timely manner with ANSYS software, it is difficult, if not impossible, to directly solve the unbalance responses by the Full method (FM) offered by ANSYS package. The reason is because the stiffness and the damping coefficients of the SFD, which are required in the computation, are in fact functions of eccentricity ratio determined by the unbalance responses. In this paper, the model of the flywheel system was firstly analyzed by QR damped method. Campbell diagram and critical speeds were then obtained from the results. Natural frequencies and their corresponding mode shapes at the rotational speed of 0.1radIcs(-1) were also calculated. Then, the unbalance responses of rotor-bearing system with SFD support were solved through iteration and through the FM with ANSYS Parametric design language routine. The comparison between the calculated unbalance responses and the experimental responses indicates that the dynamic model is valid.