An inverse solution for finite journal bearings lubricated with couple stress fluids

Elsharkawy, Abdallah A.; Guedouar, Lotfi H.

doi:10.1016/s0301-679x(00)00145-6

Cited by 46 publications

(32 citation statements)

References 26 publications

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“…Stokes [22] presented how the couple stress parameter can be obtained experimentally. The couple stress parameter can be also predicted from the pressure measurements using the inverse approach proposed by Elsharkawy and Guedouar (2001). The design parameters that describe the bearing configuration are the eccentricity ratio e, journal length-to-diameter ratio L=D, and flexibility parameter C 0 .…”

Section: Resultsmentioning

confidence: 99%

Effects of lubricant additives on the performance of hydrodynamically lubricated journal bearings

Elsharkawy

2005

Tribol Lett

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A non-Newtonian rheological model to investigate theoretically the effects of lubricant additives on the steady state performance of hydrodynamically lubricated finite journal bearings is introduced. In this model, the non-Newtonian behavior resulting from blending the lubricant with polymer additives is simulated by Stokes couple stress fluid model. The formed boundary layer at the bearing surface is described through the use of a hypothetical porous medium layer that adheres to the bearing surface. The Brinkman-extended Darcy equations are utilized to model the flow in the porous region. A stress jump boundary condition is applied at the porous media/fluid film interface. A modified form of the Reynolds equation is derived and solved numerically using a finite difference scheme. The effects of bearing geometry, and non-Newtonian behavior of the lubricant on the steady-state performance characteristics such as pressure distribution, load carrying capacity, side leakage flow, and coefficient of friction are presented and discussed. The results showed that lubricant additives significantly increase the load carrying capacity and reduce both the coefficient of friction and the side leakage as compared to the Newtonian lubricants.

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Section: Resultsmentioning

confidence: 99%

Effects of lubricant additives on the performance of hydrodynamically lubricated journal bearings

Elsharkawy

2005

Tribol Lett

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“…The couple stress parameter can be obtained experimentally 19 and it can be predicted from the pressure measurements using the inverse technique proposed by Elsharkawy and Guedouar. 20 The bearing oil film thickness varies along both axial and circumferential directions. This variation depends on the geometric configuration of the bearing such as shoulder length ratio n s , eccentricity ratio ε, and tilt angles γ 1 and γ 2 .…”

Section: Mathematical Formulationmentioning

confidence: 99%

“…Applying the central difference approximation for derivatives, equation (16) becomes (20) where (21) (22)…”

Section: Numerical Solutionmentioning

confidence: 99%

Lubricant additives effects on the hydrodynamic lubrication of misaligned conical–cylindrical bearings

Elsharkawy

2007

Lubrication Science

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Conical-cylindrical bearings are used in electrohydraulic servo systems to improve the control accuracy, eliminate the static friction and increase the normal load-carrying capacity. A non-Newtonian rheological model to investigate theoretically the effects of lubricant additives on the performance of misaligned conical-cylindrical bearings is proposed in this study. In this model, the non-Newtonian behaviour resulting from blending the lubricant with polymer additives is simulated by Stokes couple stress fluid model. The formed boundary layer at the bearing surface is described through the use of a hypothetical porous medium layer that adheres to the bearing surface. The Brinkman-extended Darcy equations are utilised to model the flow in the porous region. A stress jump boundary condition is applied at the porous media/fluid film interface. The misalignment of the cylinder rod is also considered. A modified form of the Reynolds equation is derived and solved numerically using a finite difference scheme. The effects of bearing geometry and non-Newtonian behaviour of the lubricant on the steadystate performance characteristics such as pressure distribution, load-carrying capacity and coefficient of friction are presented and discussed. The results showed that lubricant additives significantly increase the load-carrying capacity and reduce the coefficient of friction as compared to the Newtonian lubricants. Furthermore, the misalignment of the piston rod has significant effects on the performance of conical-cylindrical bearings. Copyright

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“…Several researchers have used the Stokes couple stress theory to analyse the performance characteristics of various bearing systems, such as Lin for finite journal bearing in squeeze situation, Wang et al . for journal bearing, Elsharkawy and Guedouar for finite journal bearing using a simple elastic model to determine the elastic deformation and Chu et al . for pure squeeze elasto‐hydrodynamic lubrication motion of circular contacts.…”

Section: Introductionmentioning

confidence: 99%

Coupled couple stress and surface roughness effects on elasto-hydrodynamic contact

et al. 2013

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This paper deals with the combined effects of couple stress and surface roughness to inspect the elasto‐hydrodynamic performance of slider bearing systems. On the basis of the couple stress Stokes theory and homogenisation method, the homogenised generalised Reynolds equation including the slider bearing stationary surface deformation is derived. The total deformation include the deformation of smooth surface, taken into account by the elastic thin layer model, and the deformation of roughness corresponding to a sinusoidal normal displacement on an elastic half space of identical wavelength. The governing equations are discretised by the finite difference method, and the obtained algebraic equations are solved using the iterative overrelaxation Gauss–Seidel technique. The load‐carrying capacity and friction coefficient are presented for transverse, longitudinal and anisotropic roughness patterns for different values of the couple stress parameter in both rigid and deformable cases. The simulation results indicate that the interaction between couple stress, surface roughness and elastic deformation effects is significant. Copyright © 2013 John Wiley & Sons, Ltd.

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An inverse solution for finite journal bearings lubricated with couple stress fluids

Cited by 46 publications

References 26 publications

Effects of lubricant additives on the performance of hydrodynamically lubricated journal bearings

Effects of lubricant additives on the performance of hydrodynamically lubricated journal bearings

Lubricant additives effects on the hydrodynamic lubrication of misaligned conical–cylindrical bearings

Coupled couple stress and surface roughness effects on elasto-hydrodynamic contact

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