Texture-induced effects causing reduction of friction in mixed lubrication for twin land oil control rings

Söderfjäll, Markus; Larsson, Roland; Marklund, Pär; Almqvist, Andreas

doi:10.1177/1350650117709152

Cited by 9 publications

(19 citation statements)

References 25 publications

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“…However, real solids have surface roughness on many length scales and most fluids exhibit complex rheology when confined at narrow separation between solid surfaces. Recently, theories, based on the multiscale description of the contact dynamics, have been developed for the sliding dynamics between solids with random roughness on many length scales in fluids with simple shear-thinning rheology [2][3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Lubricated sliding friction: Role of interfacial fluid slip and surface roughness

Rotella

Persson²,

Scaraggi

et al. 2020

Eur. Phys. J. E

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We derive approximate mean field equations for the fluid flow between elastic solids with randomly rough surfaces including interfacial fluid slip and shear thinning. We present numerical results for the fluid flow and friction factors for realistic systems, in particular, we consider the case of an elastic cylinder with random surface roughness in relative sliding contact with a flat rigid (low-energy) countersurface. We present experimental data for the sliding friction between rubber stoppers and glass barrels lubricated with baked-on silicone oil. We find that the frictional shear stress acting in the rubber asperity contact regions is nearly velocity independent for velocities in the 10-1000 μm/s range, and very small τ f ≈ 0.04 MPa, while for bare glass in silicone oil τ f is much larger and velocity dependent.

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Section: Introductionmentioning

confidence: 99%

Lubricated sliding friction: Role of interfacial fluid slip and surface roughness

Rotella

Persson²,

Scaraggi

et al. 2020

Eur. Phys. J. E

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“…The combustion mode showed a significant effect on lubrication performance. Liu et al [16] and Söderfjäll et al [17] proposed a mass conservative lubrication model for a dimple textured liner with a consideration of asperity contact under the mixed regime of lubrication. Based on the model, the impact of dimple geometry on the friction and power dissipation of an RLC was studied.…”

Section: Of 21mentioning

confidence: 99%

Investigation on the Frictional Performance of Surface Textured Ring-Deformed Liner Conjunction in Internal Combustion Engines

et al. 2019

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In internal combustion engines (ICEs), the frictional performance of ring-liner conjunction (RLC) has drawn special attention because it greatly affects the fuel efficiency of the engines. In recent years, surface texture (i.e., micro dimples or grooves) has emerged as a promising approach to improve the frictional performance of RLC. However, most current studies on surface textured RLC were conducted by assuming that the liner was ideally circular and the lubrication condition was either fully flooded or starved. In this study, to evaluate the frictional characteristics of an RLC with surface texture on the ring, a numerical model of lubrication is presented by considering the liner deformation, as well as the coexistence of the fully flooded and staved lubrication conditions in an engine cycle. On this basis, the frictional properties of a surface textured RLC are analyzed, and the impacts of the liner deformation and temperature on the friction-reducing effect of the surface texture are also evaluated. The results show that the surface texture on the ring can effectively reduce the power dissipation and friction dissipation of an RLC, and the reductions vary with the liner temperature and deformation. Large reductions in the power dissipation and friction dissipation of an RLC are obtained when the liner temperature is low or the liner deformation is small.

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“…It is a conventional to approach the cavitation problem by rapidly reducing the fluid density and viscosity as the pressure drops below a zero gauge to represent a transition from liquid to vapor phases. In this article, Söderfjäll's et al [47] cavitation model is adopted as described by Equation 17,…”

Section: Fluid Mechanicsmentioning

confidence: 99%

“…The micro-scale fluid density and viscosity are subsequently expressed by Equations (18) and (19), respectively, where α is threshold constant and takes a value approaching zero. The values of α and β used in this study are the same as Söderfjäll's et al [47] and are given in Table 2. Table 2.…”

Section: Fluid Mechanicsmentioning

confidence: 99%

“…Gao et al [40] used hyperbolic tangents to reduce the fluid viscosity and density to capture the change in phases over a surface feature and explore micro-cavitation. This concept was more robustly explored by Söderfjäll et al [47], who solved flows with textured surface features in oil control rings and introduced a model capable of describing the transition in phases accurately. The cavitation model of Söderfjäll et al [47] is implemented in this article as a means of capturing the effects of micro-scale cavitation.…”

Section: Introductionmentioning

confidence: 99%

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On the Two-Scale Modelling of Elastohydrodynamic Lubrication in Tilted-Pad Bearings

Boer

Almqvist

2018

Lubricants

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A two-scale method for modelling the Elastohydrodynamic Lubrication (EHL) of tilted-pad bearings is derived and a range of solutions are presented. The method is developed from previous publications and is based on the Heterogeneous Multiscale Methods (HMM). It facilitates, by means of homogenization, incorporating the effects of surface topography in the analysis of tilted-pad bearings. New to this article is the investigation of three-dimensional bearings, including the effects of both ideal and real surface topographies, micro-cavitation, and the metamodeling procedure used in coupling the problem scales. Solutions for smooth bearing surfaces, and under pure hydrodynamic operating conditions, obtained with the present two-scale EHL model, demonstrate equivalence to those obtained from well-established homogenization methods. Solutions obtained for elastohydrodynamic operating conditions, show a dependency of the solution to the pad thickness and load capacity of the bearing. More precisely, the response for the real surface topography was found to be stiffer in comparison to the ideal. Micro-scale results demonstrate periodicity of the flow and surface topography and this is consistent with the requirements of the HMM. The means of selecting micro-scale simulations based on intermediate macro-scale solutions, in the metamodeling approach, was developed for larger dimensionality and subsequent calibration. An analysis of the present metamodeling approach indicates improved performance in comparison to previous studies.

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Texture-induced effects causing reduction of friction in mixed lubrication for twin land oil control rings

Cited by 9 publications

References 25 publications

Lubricated sliding friction: Role of interfacial fluid slip and surface roughness

Lubricated sliding friction: Role of interfacial fluid slip and surface roughness

Investigation on the Frictional Performance of Surface Textured Ring-Deformed Liner Conjunction in Internal Combustion Engines

On the Two-Scale Modelling of Elastohydrodynamic Lubrication in Tilted-Pad Bearings

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