Nonlinear dynamic behaviour of vertical and horizontal rotors in compliant liner tilting pad journal bearings: Some design considerations

Cha, Matthew; Glavatskih, Sergei

doi:10.1016/j.triboint.2014.10.011

Cited by 43 publications

(19 citation statements)

References 13 publications

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“…The effects of the flexibility of the pad and pivot on the linear as well as non-linear performances of TPJBs were also studied by many authors in [31][32][33][34][35]. The pivot stiffness is usually modelled by means of the Hertz contact theory by taking into account for the material and geometry of the pivot mechanical elements, mainly the radii of curvature of the pad/pivot and bearing housing.…”

Section: Introductionmentioning

confidence: 99%

The Effect of the Pivot Stiffness on the Performances of Five-Pad Tilting Pad Bearings

2019

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The role of the pivot flexibility in tilting-pad journal bearings (TPJBs) has become essential, particularly for bearings working at high applied load and relatively high rotor speeds. Predictions from a simple bearing model with rigid pivots show incorrect estimation of the dynamic coefficients in comparison with the experimental results. Normally, the more flexible the pad pivot, the lower the dynamic coefficients because the stiffness of the pivot takes in series with the stiffness and damping of the oil film. This paper investigates the influence of pivot stiffness on the dynamic force coefficients of two different five-pad TPJBs as a function of the applied static load and excitation frequency: rocker-backed pivot and spherical pivot bearings. In order to highlight the effect of the pivot stiffness in the spherical pivot bearing, displacement restriction components and elastic copper made shims have been used. Firstly, a thermo-elasto-hydrodynamic model for the static and dynamic characteristics of the two bearings is described. This model takes into account the flexibility of both pad and pivot. The pivot stiffnesses calculated by means of the Hertz theory and those obtained by experiments have been introduced and compared in the model. The clearance profiles of two tested bearing and the shaft center loci obtained by measurement and prediction are also shown. The dynamic coefficients of the two bearings obtained from the numerical simulation were compared with the experimental results. By the analysis it can be concluded that the effect of the pivot flexibility on the clearance profile, the shaft locus and on the dynamic coefficients is very significant. More important, it is important to estimate the pivot stiffness of each single pad using experimental measurements.

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Section: Introductionmentioning

confidence: 99%

The Effect of the Pivot Stiffness on the Performances of Five-Pad Tilting Pad Bearings

2019

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“…Mü + (C + C T + ΩG)u + (K + H + K T )u = f ub (8) Where M is the mass matrix, C is the damping matrix, G is the gyroscopic matrix, K is the stiffness matrix, K T is the bearing stiffness, C T is the bearing damping, H is the bearing bracket stiffness, Ω is the rotational speed and f ub is the unbalance load. The equation of motion (8) is rewritten using state-space formulation and solved using a Runge-Kutta time integration.…”

Section: Numerical Modelmentioning

confidence: 99%

“…M. F. White et.al [7] investigated how radial clearance influenced the response using Reynold's equation to calculate the nonlinear bearing coefficients. M. Cha et.al [8] shows the difference between horizontal and vertical orientation of TPJB's using Comsol Multiphysics where Reynold's equation is solved. R. Cardinall et.al [9] modelled a hydropower rotor with TPJB's and used Reynold's equation to describe the coefficients.…”

Section: Introductionmentioning

confidence: 99%

Influence of cross-coupling stiffness in tilting pad journal bearings for vertical machines

Synnegård

Gustavsson

Aidanpää

2016

International Journal of Mechanical Sciences

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“…Bai et al [4] investigated the linear critical speed and some nonlinear dynamic characteristics of a double cantilever rotor in a large-scale turbo expander, and Li et al [5] studied those considering the viscositytemperature effect of fluid film. Cha and Glavatskih [6] investigated the nonlinear dynamic behavior of vertical and horizontal rigid rotors supported by [7] proposed an analytical hydrodynamic bearing force model using the short bearing method with the effects of turbulence and fluid inertia and investigated the effects of radial clearances, preload factors, number of pads, load positions, and pivot offsets on the rotor dynamic behavior with and without the inertia effect. Abu-Mahfouz and Adams [8] investigated the nonsynchronous and chaotic behaviors under two loading mechanisms of on-pad load and no static biasing load by changing several bearing design parameters.…”

Section: Introductionmentioning

confidence: 99%

Nonlinear dynamic analysis of low viscosity fluid-lubricated tilting-pad journal bearing for different design parameters

Jin

Chen

et al. 2019

Friction

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To reveal nonlinear dynamic rules of low viscosity fluid-lubricated tilting-pad journal bearings (TPJBs), the effects of design parameters on journal center orbits and dynamic minimum film thicknesses of waterlubricated TPJBs with and without static loads are investigated. The hydrodynamic bearing force used in the nonlinear dynamic analysis is an approximate analytical solution including the turbulence effect. The results reveal the methods for vibration suppression and load capacity improvement and give an optimal pivot offset and clearance ratio that can maximize the minimum film thickness. The results also show that four-pad TPJBs with loads between pads are preferred due to good dynamic performance and load capacity. This study would provide some guidance for nonlinear design of low viscosity fluid-lubricated TPJBs under dynamic loads.

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Nonlinear dynamic behaviour of vertical and horizontal rotors in compliant liner tilting pad journal bearings: Some design considerations

Cited by 43 publications

References 13 publications

The Effect of the Pivot Stiffness on the Performances of Five-Pad Tilting Pad Bearings

The Effect of the Pivot Stiffness on the Performances of Five-Pad Tilting Pad Bearings

Influence of cross-coupling stiffness in tilting pad journal bearings for vertical machines

Nonlinear dynamic analysis of low viscosity fluid-lubricated tilting-pad journal bearing for different design parameters

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