Theoretical And Experimental Study On Dynamic Characteristics Of Combined Elastic Support-Damper

The most commonly recurring problems in the rotor system of aero-engines are excessive steady state synchronous vibration levels. It may be reduced by introducing external damping to limit the peak amplitude at traversed critical speeds. Squeeze film damper (SFD) is a type damper widely used in aero-engines. It offers the obvious advantages of dissipation of vibration energy, as well as small volume and high reliability. But some nonlinear phenomena are generated when larger unbalance act on SFD, for instance, bistable, lockup and asynchronous whirl. These nonlinear phenomena should lead to large vibration level, rub and fatigue, which limit the operating range of SFD.This dissertation presents a new type damper, Combined Elastic Support-Damper (CESD). It is made of squirrel-cage spring and ERSFD (Elastic Ring + SFD), and can improve the nonlinear characteristics of film force, besides control vibration level.In this dissertation, the stiffness characteristics of elastic supports are analyzed, and the influence factors on them are investigated. Using Reynolds equation, the analysis model of ERSFD is theorized, and analysis program is developed. The film force characteristics of ERSFD and influence factors on them are obtained. By theoretical and experimental investigation on the rotor-CESD system, the dynamic characteristics under the influence of axial force, oil supply, structural parameters and unbalance are obtained. Finally, the damping mechanism is obtained to guide design of CESD for aero-engines.