Dynamic Analysis Of Rotor Systems With Eord Supports And Its Application In Ultra-Speed Rotating Machinery

Viscoelastic elastomer damper (VED) have been applied in rotating machinery since the middle twentieth century. VED are implemented to suppress the rotor system's vibration by dissipate dynamic energy. VED are used some abroad in high-speed rotating machinery for its simple, convenience, good vibration suppress, low costs. This thesis investigates the dynamic problem of rotor systems with Elastomer O-Rings Damper(EORD) supports and apply EORD in an ultra-speed spin tester for vibration decrement of the high-speed flexible overhung rotor.In the first part of this study, finite element motion equations are established to analysis dynamics of complex rotor system. Timoshenko beam shaft model is utilized to incorporate the flexibility of the shaft The disk is considered to be rigid and asymmetry. Unbalance and disk skew are considered in motion equation.The simulation investigations were conducted on a z-direction asymmetrically placed single-disk rotor system with two shaft ends supported in elastomer O-ring dampers. The dynamic characteristics of EORD are modeled using Kelvin-Voigt viscoelastic linear model. The effects of EORD stiffness and loss-factor and damper mass parameters on the modal frequency and stability are investigated. The results show that optimum values of the damper characteristic parameters can be achieved for a specific rotor system to improve the stability.Numerical simulations and experimental investigates were carried out for unbalance response of a single disk flexible rotor system with far shaft end mounted on EORD. Theoretical results showed that EORD, using general elastomer O-rings with loss-factor between 0.1 and 0.4, was enough to reduce first critical response vibrations of the experimental rotor system. Dynamic responses under different unbalance conditions showed excellent qualitative agreement between experimental and theoretical results.In the second part of this study, EORD is applied to an ultra-speed spin tester to support a flexible overhung rotor. The experiments with a simulated disk on the high speed shaft end was undertaken to test the EORD for the unbalance response and stability of the high-speed rotor system. The tests confirm the vibration decrement validity and linear dynamic characteristics of EORD. The spin testing of a turbine impeller with maximum spin speed 93 500 rpm was successfully finished. The finite element predictions of high critical speeds are shown to be close to the experimental results.Finally, the design guideline of EORD and the research conclusions and recommends are presented.