A Review of Tilting Pad Bearing Theory

Dimond, Timothy; Younan, Amir A.; Allaire, Paul E.

doi:10.1155/2011/908469

Cited by 67 publications

(48 citation statements)

References 71 publications

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“…Historically both numerical simulations and experimental studies in test rigs have been performed to evaluate properties of tilting pad bearings [3,4]. Glienicke et al [5] performed tests in a horizontal test rig consisting of a rotor and bearings.…”

Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Simulation of Unbalance Response in Vertical Test Rig with Tilting-Pad Bearings

Nässelqvist

Gustavsson

Aidanpää

2014

International Journal of Rotating Machinery

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In vertically oriented machines with journal bearing, there are no predefined static radial loads, such as dead weight for horizontal rotor. Most of the commercial software is designed to calculate rotordynamic and bearing properties based on machines with a horizontally oriented rotor; that is, the bearing properties are calculated at a static eccentricity. For tilting-pad bearings, there are no existing analytical expressions for bearing parameters and the bearing parameters are dependent on eccentricity and load angle. The objective of this paper is to present a simplified method to perform numerical simulations on vertical rotors including bearing parameters. Instead of recalculating the bearing parameters in each time step polynomials are used to represent the bearing parameters for present eccentricities and load angles. Numerical results are compared with results from tests performed in a test rig. The test rig consists of two guide bearings and a midspan rotor. The guide bearings are 4-pad tilting-pad bearings. Shaft displacement and strains in the bearing bracket are measured to determine the test rig's properties. The comparison between measurements and simulated results shows small deviations in absolute displacement and load levels, which can be expected due to difficulties in calculating exact bearing parameters.

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Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Simulation of Unbalance Response in Vertical Test Rig with Tilting-Pad Bearings

Nässelqvist

Gustavsson

Aidanpää

2014

International Journal of Rotating Machinery

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“…Both the definitions of the Reynolds number are the accepted methods of nondimensionalizing the flow turbulence characteristics in modern bearing treatments [30]. The calculated Reynolds numbers initially decrease and then increase in outlet ( Figure 5).…”

Section: Turbulence Modelsmentioning

confidence: 97%

“…Apart from the noted definition for the Reynolds number, an alternative reduced Reynolds number is also typically defined for considering the effect of the shaft diameter properly in bearing analyses [30]. Its definition is…”

Section: Turbulence Modelsmentioning

confidence: 99%

Numerical Investigation of Turbulence Models for a Superlaminar Journal Bearing

Ding

Ren

et al. 2018

Advances in Tribology

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With rotating machineries working at high speeds, oil flow in bearings becomes superlaminar. Under superlaminar conditions, flow exhibits between laminar and fully developed turbulence. In this study, superlaminar oil flow in an oil-lubricated tilting-pad journal bearing is analyzed through computational fluid dynamics (CFD). A three-dimensional bearing model is established. CFD results from the laminar model and 14 turbulence models are compared with experimental findings. The laminar simulation results of padside pressure are inconsistent with the experimental data. Thus, the turbulence effects on superlaminar flow should be considered. The simulated temperature and pressure distributions from the classical fully developed turbulence models cannot correctly fit the experimental data. As such, turbulence models should be corrected for superlaminar flow. However, several corrections, such as transition correction, are unsuitable. Among all the flow models, the SST model with low-Re correction exhibits the best pressure distribution and turbulence viscosity ratio. Velocity profile analysis confirms that a buffer layer plays an important role in the superlaminar boundary layer. Classical fully developed turbulence models cannot accurately predict the buffer layer, but this problem can be resolved by initiating an appropriate low-Re correction. Therefore, the SST model with low-Re correction yields suitable results for superlaminar flows in bearings.

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“…Once this parameter is defined, the pads clearances are determined, usually considering the fact that bearing housing is ideal, without dimensional changes [12]. Then, the dynamic coefficients of the journal bearing are determined, considering only the oil film hydrodynamic effects (hydrodynamic model) or including the thermal effects of bearing losses (thermohydrodynamic model) and the deformation effects produced by the oil film pressure (thermoelastohydrodynamic or TEHD model) [13]. The thermal deformations of shaft collar, bearing housing, and support of proximity transducers may have significant influence on the estimated shaft relative position shown in Figure 2.…”

Section: Introductionmentioning

confidence: 99%

Experimental Estimation of Journal Bearing Stiffness for Damage Detection in Large Hydrogenerators

Brito

Machado

Neto

2017

Shock and Vibration

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Based on experimental pieces of evidence collected in a set of twenty healthy large hydrogenerators, this article shows that the operating conditions of the tilting pad journal bearings of these machines may have unpredictable and significant changes. This behavior prevents the theoretical determination of bearing stiffness and damping coefficients with an adequate accuracy and makes damage detection difficult. Considering that dynamic coefficients have similar sensitivity to damage and considering that it is easier to monitor bearing stiffness than bearing damping, this article discusses a method to estimate experimentally the effective stiffness coefficients of hydrogenerators journal bearings, using only the usually monitored vibrations, with damage detection purposes. Validated using vibration signals synthesized by a simplified mathematical model that simulates the dynamic behavior of large hydrogenerators, the method was applied to a journal bearing of a 700 MW hydrogenerator, using two different excitations, the generator rotor unbalance and the vortices formed in the turbine rotor when this machine operates at partial loads. The experimental bearing stiffnesses obtained using both excitations were similar, but they were also much lower than the theoretical predictions. The article briefly discusses the causes of these discrepancies, the method's uncertainties, and the possible improvements in its application.

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A Review of Tilting Pad Bearing Theory

Cited by 67 publications

References 71 publications

Experimental and Numerical Simulation of Unbalance Response in Vertical Test Rig with Tilting-Pad Bearings

Experimental and Numerical Simulation of Unbalance Response in Vertical Test Rig with Tilting-Pad Bearings

Numerical Investigation of Turbulence Models for a Superlaminar Journal Bearing

Experimental Estimation of Journal Bearing Stiffness for Damage Detection in Large Hydrogenerators

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