Research On Structural And Dynamic Characteristics Of Floating Ring Squeeze Film Damper

Dynamic characteristics were studied for a rotor supported on floating-ring squeeze film dampers(FSFD) in this paper according to high nonlinear of traditional squeeze film damper. The results wereimportant to solve vibration of aircraft engine. The main harvests and conclusions of research asfollowing:(1) Reynolds equations of inner and outer film of FSFD were derived basing on the generalizedReynolds equation, wall friction equation and Hirs overall flow theory. Dynamic model of FSFD wereestablished according to the balance between the inner and outer film pressure, and provided bettertheoretical foundation for FSFD dynamic characteristics analysis.(2)The calculation program was written basing on finite difference method and according to themodel in the article. The characteristic influences were studied for FSFD about the structural and filmparameters. The results showed that the equivalent damping was greater for the FSFD witheccentricity small, the width wider and clearance of film bigger. The equivalent damping decreases asoil temperature increasing for the FSFD. Nonlinear were obviously improved for the FSFD comparingwith the traditional SFD.(3) The model was established for the single rotor system with the FSFD taking into account thenonlinear force of oil film. The critical speeds, steady state response for an unbalance,non-synchronous whirling response and instantaneous response for a sudden unbalance werecalculated for the system. The results showed the steady state response for the unbalance wassignificantly smaller in the FSFD-rotor system than in non FSFD-rotor system. The effect of reducingvibration was validated. According to the bifurcation, non-synchronous whirling response arecalculated for the FSFD-rotor system with unbalance, speed, weight of floating ring, oil viscosity,width of film and thickness of oil. Non-synchronous whirling response range of the rotor decreased asunbalance, oil clearance, viscosity coefficient and width of film increasing, and appropriate quality offloating ring could inhibit non-synchronous whirling response of FSFD-rotor system. Effects of speed, stiffness of support and weight of floating ring on sudden unbalance response of FSFD-rotorsystem were calculated. The performance of FSFD was better than traditional SFD to prevent suddenunbalance response.(4) The dynamic characteristics of FSFD were validated making use of two orthogonallydirections exciting test rig. The influences were studied for exciting force, oil clearance and width offilm on the film pressure. The experimental results identified well to theoretical calculating results.The correctness of the model was proved in the paper and it possessed a good directing significancefor engineering application.The results of research provided theoretical foundation for further researching and engineeringapplication to FSFD as well as the rotor system in the paper.