Wall slip effects in (elasto) hydrodynamic journal bearings

Fatu, Aurelian; Maspeyrot, Patrick; Hajjam, Mohamed

doi:10.1016/j.triboint.2011.03.003

Cited by 107 publications

(93 citation statements)

References 24 publications

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“…And, the higher is the rotating speed, the larger is the possibility of existence of wall slip. This conclusion is consistent with the previous achievements in references [19,23,25,29,36]. The modified model is more accurate in the prediction of friction coefficient for water lubricated PTFE bearing.…”

Section: Comparison Of Experimental and Theoretical Resultssupporting

confidence: 92%

“…When the velocity meets the requirement u > u c , we can not say that all the lubricant molecules on the surface occur to slip. Some of the literatures [23,[27][28][29][30] have proposed a simple criterion to distinguish whether wall slip effect has occurred on the solid-liquid interface through theoretical and experimental researches. When the interface tension of the lubricant medium becomes bigger than that of the friction pair material, namely, adhesion fracture occurs before the cohesive fracture of molecular bonds, then the wall slip is very likely to happen.…”

Section: Theoretical Basis Of Wall Slipmentioning

confidence: 99%

“…For instance, Spikes et al [22], analyze the influence of slippage on the fluid dynamic behaviors when the wall slip phenomenon occurs on the static slider surface, finding that the bearing load capacity is exactly half of the case with no slippage when the limiting shear stress equals to zero, but the corresponding friction is reduced by several orders of magnitude. Aurelian [23] investigates wall slip effects on elasto-hydrodynamic journal bearings and the study extended to the influence of wall slip in highly loaded compliant bearings for steady-state and dynamical load conditions. It also predicts that well-chosen slip/no-slip surface pattern can considerably improve the bearing behavior and largely justify future numerical and experimental works.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Theoretical and experimental research on the friction coefficient of water lubricated bearing with consideration of wall slip effects

Xie

Rao

Liu

et al. 2015

Mechanics & Industry

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-Researches of the nature of friction coefficient of water lubricated bearing are carried out in this paper. Based on the experimental results of composite material bearing under hydrodynamic lubrication by water, we calculate the Stribeck curves as the function of load and speed, deviate the modified Reynolds equation considering wall slip effects in Cartesian coordinate system, put forward the essential model of friction coefficient, the composition of friction coefficient and essential changing correlation between them. Numerical results are in good agreement with experimental results, which verifies existence of wall slip. Researches indicate that there is always an appropriate working condition which friction coefficient is minimum. Comparison of the theoretical and experimental results shows that they are consistent on the overall trend but still exist some deviations under certain operating conditions. Reasonable explanations are given to illustrate the correctness of theoretical model. Key words:Water lubricated bearing / nature of friction coefficient / wall slip effect / solid contact effect and fluid viscous effect / experimental research

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Section: Comparison Of Experimental and Theoretical Resultssupporting

confidence: 92%

Section: Theoretical Basis Of Wall Slipmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Theoretical and experimental research on the friction coefficient of water lubricated bearing with consideration of wall slip effects

Xie

Rao

Liu

et al. 2015

Mechanics & Industry

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“…In the case of incompressible flow with negligible inertia effects, the force and torque on the load bearing inner cylinder decreases with increasing slip. Aurelian et al (2011) experimented with regions of slip and no-slip on journal bearing faces. Results show well chosen no-slip and slip regions can considerably improve the dynamical bearing predictions whilst an inadequate no-slip and slip pattern can lead to a deterioration in the bearing behaviour.…”

Section: Introductionmentioning

confidence: 99%

Dynamics of a small gap gas lubricated bearing with Navier slip boundary conditions

2017

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A gas lubricated bearing model is derived which is appropriate for a very small bearing face separation by including velocity slip boundary conditions and centrifugal inertia effects. The bearing dynamics are examined when an external harmonic force is imposed on the bearing due to bearing begin situated within a larger complex dynamical system. A compressible Reynolds equation is formulated for the gas film which is coupled to the bearing structure through an axial force balance where the rotor and stator correspond to spring-mass-damper systems. Surface slip boundary conditions are derived on the bearing faces, characterised by the slip length parameter. The coupled bearing system is analysed using a stroboscopic map solver with the modified Reynolds equation and structural equations solved simultaneously. For a sufficiently large forcing amplitude a flapping motion of the bearing faces is induced when the rotor and stator are in close proximity. The minimum bearing gap over the time period of the external forcing is examined for a range of bearing parameters.

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“…The inclusion of inertial effects via the generalised Reynolds equation [17] or Navier-Stokes equations illustrated the influence of inertia on load capacity and the consequent benefit of using Computational Fluid Dynamics (CFD) to model the fluid film flow. CFD has also been used on smooth geometries to enable the modelling of a range of phenomena which occur in EHL such as thermal transport, rheology, cavitation [18], wall slip [19] and structural models [20]. Both deterministic (where the surface topographical features are fully described and resolved over the global domain) and homogenisation (where the flow about surface topographical features are solved independently and the results are applied to the global domain) models have been used by researchers to analyse bearings with surface texturing.…”

Section: Introductionmentioning

confidence: 99%

Two-scale EHL: Three-dimensional topography in tilted-pad bearings

Boer

Hewson

Thompson

et al. 2014

Tribology International

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Derived from the Heterogeneous Multiscale Methods (HMM), a two-scale method is developed for the analysis of Elastohydrodynamic Lubrication (EHL) and micro-EHL in tilted-pad bearings with threedimensional topography. A relationship linking the pressure gradient to mass flow rate is derived and represented in the bearing domain through homogenisation of near-periodic simulations describing the Fluid Structure Interaction (FSI) of topographical features. For the parameters investigated the influence of compressibility and piezoviscosity was found to be more significant than that of non-Newtonian (shear-thinning) behaviour on textured bearing performance. As the size of topography increased twoscale solutions demonstrated that at constant load the coefficient of friction increased and the minimum film thickness decreased over a range of pad lengths and tilt angles.

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Wall slip effects in (elasto) hydrodynamic journal bearings

Cited by 107 publications

References 24 publications

Theoretical and experimental research on the friction coefficient of water lubricated bearing with consideration of wall slip effects

Theoretical and experimental research on the friction coefficient of water lubricated bearing with consideration of wall slip effects

Dynamics of a small gap gas lubricated bearing with Navier slip boundary conditions

Two-scale EHL: Three-dimensional topography in tilted-pad bearings

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