Stability of Squeeze Film Damped Multi-Mass Flexible Rotor Bearing Systems

McLean, L. J.; Hahn, E. J.

doi:10.1115/1.3261094

Cited by 20 publications

(8 citation statements)

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“…4 and on the section CD are unstable as the modulus of the first Floquet multiplier is larger than one. These results are identical to those given by McLean and Hahn (1985), but they did not identify the type of the predicted instability or the possible stable rotor responses in these regions.…”

Section: Concentric Damper Operationsupporting

confidence: 87%

Stability and Bifurcation of Unbalanced Response of a Squeeze Film Damped Flexible Rotor

Zhao

Linnett

McLean³

1994

Journal of Tribology

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The stability and bifurcation of the unbalance response of a squeeze film dampermounted flexible rotor are investigated based on the assumption of an incompressible lubricant together with the short bearing approximation and the "it "film cavitation model. The unbalanced rotor response is determined by the trigonometric collocation method and the stability of these solutions is then investigated using the Floquet transition matrix method. Numerical examples are given for both concentric and eccentric damper operations. Jump phenomenon, subharmonic, and quasi-periodic vibrations are predicted for a range of bearing and unbalance parameters. The predicted jump phenomenon, subharmonic and quasi-periodic vibrations are further examined by using a numerical integration scheme to predict damper trajectories, calculate Poincare maps and power spectra. It is concluded that the introduction of unpressurized squeeze film dampers may promote undesirable nonsynchronous vibrations.

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Section: Concentric Damper Operationsupporting

confidence: 87%

Stability and Bifurcation of Unbalanced Response of a Squeeze Film Damped Flexible Rotor

Zhao

Linnett

McLean³

1994

Journal of Tribology

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“…The rigid critical speed of the #exible rotor system is the pin}pin critical speed when both ends of the #exible rotor are mounted rigidly; the #exible critical speed of the #exible rotor system is the translational critical speed when both ends of the #exible rotor are mounted on the centralizing springs. By using a perturbation method as in reference [3], it is shown that the largest and smallest solutions shown in solid lines are stable and the medium one shown in dotted line is unstable.…”

Section: Solution Of Synchronous Circular Centred-orbit Motionmentioning

confidence: 98%

Analysis of the Multiple-Solution Response of a Flexible Rotor Supported on Non-Linear Squeeze Film Dampers

Zhu¹,

Robb

Ewins

2002

Journal of Sound and Vibration

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“…In this case, the continuous rotor model is discretized and a finite number of DOFs are introduced. The dynamics of multi-mass and multi-degrees of freedom (MDOF) rotors supported with SFDs is theoretically studied in [43,44]. The precedent studies assumed that the effect of lubricant inertia on the fluid film reaction forces in SFDs is negligible and either used the complete or the approximate (i.e., long bearing and short bearing approximations) Reynolds equation to represent the SFD dynamics.…”

Section: Introductionmentioning

confidence: 99%

A Study of Lubricant Inertia Effects for Squeeze Film Dampers Incorporated into High-Speed Turbomachinery

Hamzehlouia

Behdinan

2017

Lubricants

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This work proposes a numerical model that incorporates the effect of lubricant inertia on the hydrodynamic pressure distribution, fluid film reaction forces, and the fluid velocity component profiles for finite-length open-ended squeeze film dampers (SFDs). Firstly, the thin film flow equations for the SFD in presence of fluid inertia effects are introduced. Furthermore, a small first-order perturbation by means of the expressions for the fluid film velocity components and the lubricant pressure distribution that are expanded in power series of the squeeze film Reynolds number is applied to the flow equations. Subsequently the developed lubricant flow equations are solved to develop expressions for the velocity component profiles and the hydrodynamic pressure distribution in SFDs. The pressure expression is numerically solved by using Gauss-Seidel method with finite difference discretization. Moreover, the fluid film reaction forces are determined by numerically integrating the hydrodynamic pressure expressions over the journal surface. Additionally, the proposed pressure distribution expression and the numerical SFD forces are incorporated into a simulation model and the simulation results are compared with the existing models in the literature under different operating conditions, including eccentricity ratios and inertia effects (i.e., Reynolds numbers). The simulation results demonstrate the significant influence of both convective and temporal (i.e., unsteady) lubricant inertia terms on the SFD hydrodynamic pressure distribution and the fluid film reaction forces. Furthermore, the proposed SFD model is incorporated into a multi-mass flexible rotordynamic model to evaluate the effect of SFD fluid inertia on the mass unbalance induced steady-state vibrations of the rotor and the nodal transient orbits by implementing finite element method and transient modal integration with predictor-corrector solver. The results of the analysis demonstrate the significant effect of fluid inertia on the resonance frequencies of the rotor and the steady-state vibration amplitudes and the transient orbits at the resonance zone.

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Stability of Squeeze Film Damped Multi-Mass Flexible Rotor Bearing Systems

Cited by 20 publications

References 0 publications

Stability and Bifurcation of Unbalanced Response of a Squeeze Film Damped Flexible Rotor

Stability and Bifurcation of Unbalanced Response of a Squeeze Film Damped Flexible Rotor

Analysis of the Multiple-Solution Response of a Flexible Rotor Supported on Non-Linear Squeeze Film Dampers

A Study of Lubricant Inertia Effects for Squeeze Film Dampers Incorporated into High-Speed Turbomachinery

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