Unsteady oil film forces in porous bearings: analysis of  permeability effect on the rotor linear stability

D'Agostino, V.; Ruggiero, Alessandro; Senatore, Adolfo

doi:10.1007/s11012-008-9180-0

Cited by 18 publications

(13 citation statements)

References 13 publications

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“…The problem of dynamic instability for fluid-film journal bearings is of basic importance in high-speed modern rotating machines. [1][2][3][4][5][6][7][8] The oil whip/whirl instability occurs when the angular velocity exceeds a particular value, and shows a self-excited orbital motion induced by the action of the non-linear fluid forces. This motion can produce significant mechanical complications, like rubbing between the journal and the bearing, impacts between blades and stator in turbo-machines, or more usually vibrations of the whole rotating machinery.…”

Section: Introductionmentioning

confidence: 99%

“…12,13 Many theoretical and experimental investigations were dedicated to the investigation of the dynamic behaviour of journal bearings. [1][2][3]5,[7][8][9][11][12][13][14][15][16][17] Numerical techniques, based on the finite difference (or the finite element) procedure, were used by several authors to solve the Reynolds' equation. In most cases, these methods are devoted to the calculation of the bearing stiffness and damping coefficients.…”

Section: Introductionmentioning

confidence: 99%

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Analytical fluid film force calculation in the case of short bearing with a fully developed turbulent flow

Ruggiero

Hloch

Kozak

et al. 2015

Proceedings of the Institution of Mechanical Engineers, Part J:

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The main purpose of this paper is to define a methodology to determine the analytical approximate closed-form expression of non-steady fluid film force and of the oil film coefficients for the liquid-lubricated journal bearings in the case of a fully developed turbulent flow regime. The considered model is a symmetrical rigid rotor supported on two lubricated journal bearings; this paper considers the cases of the short bearing approximation, introducing the turbulence correction flow factors in the classical Reynolds equation. The proposed methodology gives the opportunity to solve in approximate way the equation governing the distribution of pressure in the bearing oil gap and then to obtain the closed- form expressions for the non-steady fluid forces. This approach shows the benefit of minimising the calculation time required for the non-linear dynamic analysis of rotors on turbulent journal bearings without any significant loss of accuracy giving a better readability of the parameter involved on the system behaviour

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Analytical fluid film force calculation in the case of short bearing with a fully developed turbulent flow

Ruggiero

Hloch

Kozak

et al. 2015

Proceedings of the Institution of Mechanical Engineers, Part J:

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“…Tang 7 used a finite element method based on rectangular isoparametric element for evaluating the stiffness and damping coefficients of hydrodynamic bearings, which was verified by calculated the pressure distribution of a short bearings and dynamic coefficients. Agostino et al 8 identified the journal stability threshold by using an original approximate analytical approach for the nonsteady fluid film force and the stiffness and damping coefficients description in the case of low loaded porous journal bearings. Zarbane et al 9 presented a numerical study of the behavior of fluid film subjected to a periodic squeeze action which showed the effects of the frequency and the average film thickness on the film load-carrying ant the rupture.…”

Section: Introductionmentioning

confidence: 99%

“…Agostino et al. 8 identified the journal stability threshold by using an original approximate analytical approach for the nonsteady fluid film force and the stiffness and damping coefficients description in the case of low loaded porous journal bearings. Zarbane et al.…”

Section: Introductionmentioning

confidence: 99%

Analysis of hydrodynamic loads on performance characteristics of engine main bearings

Shao

Liu

et al. 2014

Proceedings of the Institution of Mechanical Engineers, Part J:

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This article aims to present a numerical study of the behavior of engine main bearings under dynamic load. The coupling performance characteristics of oil film between crankshaft and engine block are analyzed. The film pressure is solved numerically with Reynolds boundary conditions when various bearing characteristics are calculated. Hydrodynamic lubrication is analyzed with finite difference method for solving the Reynolds equation for thermo effect. The other models, such as engine block and crankshaft-connecting rod system, are processed by utilizing the finite element method. Above this system, model applied in this paper is simulated by employing multi-body dynamic method to capture the dynamic characteristics of engine dynamic simulation. Through the methods mentioned above, the performance characteristics of engine main bearings under hydrodynamic loads in a six-cylinder in-line diesel engine were received. And the orbit movement, minimum oil film thickness, and power loss in the bearing were estimated over the wide range of engine operation.

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“…Other works focus on detailed material modelling, where distribution, diameter and connectivity of pores are considered in a probabilistic analysis . D'Agostino et al . investigate rotor‐bearing stability as a function of material permeability but not in a probabilistic way.…”

Section: Introductionmentioning

confidence: 99%

The effect of permeability distribution on the numerical analysis of aerostatic ceramic porous bearings

Nicoletti

Purquerio

Silveira

2012

Lubrication Science

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This work presents a numerical study on the effect of permeability on the static characteristics of aerostatic ceramic porous bearings. This study is important in bearing design because of the inherent permeability variation of the porous ceramic samples induced by manufacturing and sintering processes. The mathematical modelling of these bearings is based on the modified Reynolds equation, which depends on the pressure‐flow assumption (Darcy or Forchheimer) and on the static and dynamic permeability coefficients of the porous matrix. In this work, the modified Reynolds equation is numerically solved considering the variations of permeability values, whose distribution was obtained from experimental tests of the ceramic samples. Monte Carlo method is used to introduce variability in the solutions. One focuses on the effects of such variation on the results of predicted bearing loading capacity. Results show that optimum regions of the bearing load capacity do not vary significantly due to static and dynamic permeability variations. Copyright © 2012 John Wiley & Sons, Ltd.

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Unsteady oil film forces in porous bearings: analysis of permeability effect on the rotor linear stability

Cited by 18 publications

References 13 publications

Analytical fluid film force calculation in the case of short bearing with a fully developed turbulent flow

Analytical fluid film force calculation in the case of short bearing with a fully developed turbulent flow

Analysis of hydrodynamic loads on performance characteristics of engine main bearings

The effect of permeability distribution on the numerical analysis of aerostatic ceramic porous bearings

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