Temporal and Convective Inertia Effects in Plain Journal Bearings With Eccentricity, Velocity and Acceleration

Dousti, Saeid; Cao, Jiangbei; Younan, Amir A.; Allaire, Paul E.; Dimond, Tim

doi:10.1115/1.4006928

Cited by 27 publications

(12 citation statements)

References 17 publications

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“…In the frequency domain, Equation (33) leads to the frequency response function given by Equation (34):…”

Section: Transient Pure Squeeze Motion Between Infinite Parallel Platesmentioning

confidence: 99%

“…As a result, there are no added mass effects within the load resulting from Reynolds equation and for that reason alone a spring-damper model should be used to model the bearing dynamic behavior in the present work. Added mass coefficients (inertia parameters) would be required if inertia effects were retained within the Reynolds equation as in Dousti [33].…”

Section: Transient Pure Squeeze Motion Between Infinite Parallel Platesmentioning

confidence: 99%

“…The time domain estimate can be made by solving the overdetermined system, Equation (33), for the bearing parameters K, D, and M:…”

Section: Transient Pure Squeeze Motion Between Infinite Parallel Platesmentioning

confidence: 99%

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Comparison of Perturbed Reynolds Equation and CFD Models for the Prediction of Dynamic Coefficients of Sliding Bearings

Snyder

Braun

2018

Lubricants

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Abstract:The accuracy and utility of rotordynamic models for machinery systems are greatly affected by the accuracy of the constituent dynamic bearing models. Primarily, the dynamic behavior of bearings is modeled as linear combination of mass, damping, and stiffness coefficients that are predicted from a perturbed Reynolds equation. In the present paper, an alternative method using Computational Fluid Dynamics (CFD) with a moving boundary is used to predict the dynamic coefficients of slider bearings and the results are compared with the more commonly employed perturbed Reynolds equation model. A linear slider bearing geometry is investigated and the results serve as precursors to similar investigations involving the more complex journal bearing geometries. Time and frequency domain methods for the estimation of dynamic coefficients are shown to give comparable results. For CFD with a moving boundary, temporal inertia is found to have a significant effect for a reduced, squeeze Reynolds number less than one. The temporal inertia effect is captured through an added mass coefficient within the dynamic model of the bearing.

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“…In the frequency domain, Equation (33) leads to the frequency response function given by Equation (34):…”

Section: Transient Pure Squeeze Motion Between Infinite Parallel Platesmentioning

confidence: 99%

Section: Transient Pure Squeeze Motion Between Infinite Parallel Platesmentioning

confidence: 99%

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Comparison of Perturbed Reynolds Equation and CFD Models for the Prediction of Dynamic Coefficients of Sliding Bearings

Snyder

Braun

2018

Lubricants

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“…Furthermore, the axial momentum flux integral is approximated as follows 30 where for small to moderate squeeze Reynolds numbers a value of α = 1.2 is assigned for all the calculations. 18 Consequently hence: …”

Section: Derivation Of the Sfd Modelmentioning

confidence: 99%

Squeeze film dampers supporting high-speed rotors: Fluid inertia effects

Hamzehlouia

Behdinan

2019

Proceedings of the Institution of Mechanical Engineers, Part J:

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This work represents closed-form analytical expressions for the operating parameters for short-length open-ended squeeze film dampers, including the lubricant velocity profiles, hydrodynamic pressure distribution, and lubricant reaction forces. The proposed closed-form expressions provide an accelerated calculation of the squeeze film damper parameters, specifically for rotordynamics applications. In order to determine the analytical solutions for the squeeze film damper parameters, the thin film equations for lubricant are introduced in the presence of the influence of lubricant inertia. Subsequently, two different analytical techniques, namely the momentum approximation method, and the perturbation method are applied to the thin film equations. Moreover, the solution for the lubricant flow equations are analytically determined to represent closed-form expressions for the hydrodynamic pressure distribution and the velocity component profiles in squeeze film dampers. Additionally, the expressions for the hydrodynamic pressure distribution are integrated over the journal surface, either numerically or analytically by using Booker’s integrals, to develop expressions for the fluid film reaction forces. Lastly, the developed squeeze film damper models are incorporated into simulation models in Matlab and Simulink®, and the results are compared against a well-established force coefficient model to verify the accuracy of the calculations. The results of the simulations verify the effect of the lubricant inertia components, namely the convective and temporal (i.e., unsteady) inertia components on the squeeze film damper dynamics, including hydrodynamic pressure distribution and fluid film reaction forces. Additionally, the simulation results suggest a close agreement between the proposed models and the results in the literature.

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“…The contribution of lubricant inertia on the damping capacity of SFDs was theoretically and experimentally investigated in several studies. [31][32][33] The theoretical studies typically focus on developing solutions for the SFD lubricant pressure profile and reaction forces, including: closed-form analytical expressions, [34][35][36][37] numerical procedures, 1,[38][39][40][41] force coefficients to represent the direct and cross-coupled inertia and damping. [42][43][44][45] and limiting damper geometries.…”

Section: Introductionmentioning

confidence: 99%

Squeeze film dampers supporting high-speed rotors: Rotordynamics

Hamzehlouia

Behdinan

2020

Proceedings of the Institution of Mechanical Engineers, Part J:

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This work develops a finite element based multi-mass flexible rotor model for theoretical investigation of the influence of the squeeze film damper lubricant inertia on the unbalance-induced steady-state and transient vibration amplitudes of high speed turbomachinery. The rotordynamic model is developed by applying the principles of finite element analysis to discretize the rotor components, including the rotor shaft and disk, into local elements with mass, stiffness, and gyroscopic matrices. Subsequently, the local matrices are assembled together to develop the global model of the rotordynamic system. The influence of squeeze film damper lubricant inertia is incorporated into the model by using short-length cavitated damper models with retaining springs executing circular-centered orbits. Additionally, the rotordynamic model incorporating the nonlinear squeeze film damper models is iteratively solved in the time domain by applying a predictor-corrector transient modal integration numerical method and the steady-state and transient motions of the rotor system are investigated under different rotor and squeeze film damper parameters. The results of the study verify the substantial influence of squeeze film damper lubricant inertia on attenuating the vibrations of high-speed turbomachinery. Furthermore, the developed rotordynamic model delivers an efficient and powerful platform for the analysis of high-speed turbomachinery, including jet engines and gas turbines.

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Temporal and Convective Inertia Effects in Plain Journal Bearings With Eccentricity, Velocity and Acceleration

Cited by 27 publications

References 17 publications

Comparison of Perturbed Reynolds Equation and CFD Models for the Prediction of Dynamic Coefficients of Sliding Bearings

Comparison of Perturbed Reynolds Equation and CFD Models for the Prediction of Dynamic Coefficients of Sliding Bearings

Squeeze film dampers supporting high-speed rotors: Fluid inertia effects

Squeeze film dampers supporting high-speed rotors: Rotordynamics

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