Analysis of the effect of floating ring squeeze film damper on sudden unbalance response of low pressure rotor

To research the depression effect of floating ring squeeze film damper on sudden unbalance response of low pressure rotor in turboshaft engine, a dynamical simplified model of low pressure rotor supported on floating ring squeeze film damper was built, considering multiple dynamical coupling. Its motion equations were derived and solved by the numerical method. The influence of some parameters, e.g., mass ratio between floating ring and bearing, stiffness of elastic support, and film clearance, were analyzed. The main results are as follow: compared with traditional squeeze film damper, the floating ring squeeze film damper has better performance in depressing both critical transient responses and sudden unbalance responses in steady-state process or in accelerating process; with greater mass ratio between floating ring and bearing, smaller stiffness of elastic support and smaller film clearance, the floating ring squeeze film damper has better performance in depressing both transient amplitude and transient time of sudden unbalance responses; the speed range with large vibration of rotor system during passsing through the bistable region depends not only on the mass ratio between floating ring and bearing, but also on the film damper clearance; it decreases along with the mass ratio increases, and increases with the film clearance decreases.