A Chambered Porous Damper for Rotor Vibration Control: Part II—Imbalance Response and Blade-Loss Simulation

In this paper, results of experimental rotordynamic evaluations of a novel, high load chambered porous damper design are presented. The chambered porous damper concept was evaluated for gas turbine engine application since this concept avoids the nonlinearities associated with high-eccentricity operation of conventional squeeze film dampers. The rotordynamic testing was conducted under large steady-state imbalance and simulated transient bladeloss conditions for up to 0.254 mm (0.01 in.) mass c.g offset or 180 g-cm (2.5 oz-in.) imbalance. The chambered porous damper demonstrated that the steady-state imbalance and simulated blade-loss transient response of a flexible rotor operating above its first bneding critical speed could be readily controlled. Rotor system imbalance sensitivity and logarithmic decrement are presented showing the characteristics of the system with the damper installed. The ability to accommodate high steady-state and transient imbalance conditions makes this damper well suited to a wide range of rotating machinery, including aircraft gas turbine engines.