Analytical analysis and optimisation of the Rayleigh step slider bearing

Rahmani, Ramin; Shirvani, Ayoub; Shirvani, Hassan

doi:10.1016/j.triboint.2008.09.002

Cited by 39 publications

(33 citation statements)

References 10 publications

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“…In fact, by increasing the number of textures and/or reducing the area density of textures, Λ W and Ω reduce whilst μ M increases uniformly regardless of the variations of the other independent variables in the given range. This result is in line with the previous observations that in the case of m=1 or Sp=1, the resultant bearing would be the Rayleigh step which is known as the bearing with the best tribological performance amongst all other bearing surface profiles (see [27]). Therefore, to find a typical set of optimum value(s) for the rest of independent variables a constant textures length to distance ratio will be assumed.…”

Section: Figuresupporting

confidence: 92%

An analytical approach for analysis and optimisation of slider bearings with infinite width parallel textures

Rahmani

Mirzaee

Shirvani

et al. 2010

Tribology International

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121

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This paper introduces an analytical approach to study the textured surfaces in hydrodynamic lubrication regime. For this purpose, a method of integrating the Reynolds equation for slider bearings with surface discontinuities is presented. By introducing appropriate dimensionless parameters, analytical relations for various texture profiles in both indented and projected forms are delivered. These relations express the nature of mathematical dependence between textured bearing performance measures and geometrical/operational parameters. An optimisation procedure is employed to achieve the optimum texturing parameters promoting maximum load capacity, load capacity to lubricant flow rate ratio and minimum friction coefficient for asymmetric partially textured slider bearings. Keywords IntroductionIt is now widely accepted that introducing artificially created micro-features onto sliding surfaces can significantly affect friction and wear of the sliding bearings. It is further believed that the textured surfaces provide the best performance amongst all other mechanical surface treatments [1]. The positive effect of artificial surface texturing on enhancing the load capacity, wear resistance and/or friction coefficient of mechanical seals [2], piston-ring/cylinder liner mechanism in internal combustion engines [3,4,5] and roller/piston in hydraulic motors [6] as some of the application examples are shown through numerical and/or experimental studies.Considering the associated theoretical studies, in a pioneering work by Salama [7], the effect of macro-roughness induced by manufacturing process in the form of surface waviness on the slider bearing performances was studied. As a result, existence of an optimum waviness length to amplitude was reported. By developing a theoretical model to obtain pressure distribution for a single micro-asperity and then, spreading the results for a population of asperities mounted on a radial face seal, Hamilton et al [8] notified existence of an optimum range for asperity height and asperity area fraction providing the maximum loads support. They suggested further research on the effect of interactions amongst asperities. On the other hand, an analytical/experimental study on microasperity lubrication by Anno et al [9] proposed that the poorer correlation between experimental and theoretical results in [8] could be improved by considering the hydrodynamic load support induced by small tilts on the tops of asperities. Later on, Anno et al [10] extended the study to 'negative asperities' and concluded that although all shape of asperities (whether positive or negative) of comparable dimension produce similar load support, to avoid leakage, one must utilise negative asperities.The study of tribological effects obtained by introducing surface microfeatures was brought to the centre of attention again by Etsion and Burstein [11] who focused on the study of the effect of shallow pores on the operational behaviour of the mechanical face seals. They solved the Reynolds equation numer...

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Section: Figuresupporting

confidence: 92%

An analytical approach for analysis and optimisation of slider bearings with infinite width parallel textures

Rahmani

Mirzaee

Shirvani

et al. 2010

Tribology International

Self Cite

121

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“…This results can be found also in a recent work by Rahmani et al [75], where they made an analysis of the Rayleigh Step analytically. They based their work on the Reynolds equation considering non-homogeneous boundary conditions for pressure.…”

Section: Friction Force Of the Step Wedgesupporting

confidence: 77%

Modelação matemática de contatos lubrificados micro-texturizados

Palma¹

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“…Since then, researches into optimum design and fluid dynamic characteristics of this bearing have attracted much attention [6,7]. Rahmani et al [8] comprehensively studied the Rayleigh step slider bearing including the effect of variations of pressure at the boundaries on the optimum parameters. The bearing is also optimized considering the lubricant flow rate, friction force, and friction coefficient.…”

Section: Introductionmentioning

confidence: 99%

Recirculation Flow and Pressure Distributions in a Rayleigh Step Bearing

Shen

Yan

Dai

et al. 2018

Advances in Tribology

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Flow characteristics in the Rayleigh step slider bearing with infinite width have been studied using both analytical and numerical methods. The conservation equations of mass and momentum were solved utilizing a finite volume approach and the whole flow field was simulated. More detailed information about the flow patterns and pressure distributions neglected by the Reynolds lubrication equation has been obtained, such as jumping phenomenon around a Rayleigh step, vortex structure, and shear stress distribution. The pressure distribution of the Rayleigh step bearing with optimum geometry has been numerically simulated and the results obtained agreed with the analytical solution of the classical Reynolds lubrication equation. The simulation results show that the maximum pressure of the flow field is at the step tip not on the lower surface and the increment of the strain rate from Navier-Stokes equation is approximately 49 percent greater than that from Reynolds theory at the step tip. It is also shown that the position of the maximum pressure of the lower surface is a little less than the length of the first region. These results neglected by the Reynolds lubrication equation are important for designing a bearing.

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Analytical analysis and optimisation of the Rayleigh step slider bearing

Cited by 39 publications

References 10 publications

An analytical approach for analysis and optimisation of slider bearings with infinite width parallel textures

An analytical approach for analysis and optimisation of slider bearings with infinite width parallel textures

Modelação matemática de contatos lubrificados micro-texturizados

Recirculation Flow and Pressure Distributions in a Rayleigh Step Bearing

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