Particle Entrapment in Line Elastohydrodynamic Contacts and the Influence of Intermolecular (van der Waals) Forces

A metallic particle passing through concentrated rolling-sliding contacts is often linked to surface damage for particles larger than the available gap. At the instant of particle pinching, force balancing dictates particle entrapment and passing through the contact or rejection. It is vital to include all major forces in this process. This study revisits the analytical entrapment model previously published by the author for spherical micro-particles by incorporating a force so far overlooked in related studies, namely the van der Waals intermolecular force and, additionally, surface roughness effects. In conjunction with particle mechanical and fluid forces, this provides an almost complete set to use for correct force balancing. A parametric analysis shows the effect of several geometrical, mechanical, rheological, and surface parameters on spherical particle entrapment and reveals the significance of the van der Waals force for particles smaller than about 5–10 μm in diameter.

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Particle entrapment in elliptical, elastohydrodynamic, rough contacts and the influence of intermolecular (van der Waals) forces

Proceedings of the Institution of Mechanical Engineers Part J Journal of Engineering Tribology ◽

10.1177/13506501211000184 ◽

2021 ◽

pp. 135065012110001

Author(s):

George K Nikas

Keyword(s):

Parametric Analysis ◽

Van Der Waals ◽

Intermolecular Forces ◽

Intermolecular Force ◽

Performance Indices ◽

Roughness Effects ◽

Particle Entrapment ◽

And Performance ◽

Particle Force ◽

Lubricant Viscosity

The entrapment/rejection process of spherical, rigid microparticles in elliptical, rough elastohydrodynamic contacts is modelled. An earlier model of the author is extended to include van der Waals intermolecular forces, in addition to mechanical (reaction and friction) and fluid–particle forces. Surface roughness effects are also introduced in terms of the intermolecular force formulation and in the microscale friction (particle–asperity) sub-model. Possibilities related to particle entry into a contact are quantified by weight factors and performance indices. A total entrapment index is defined and linked to the probability of particle entrapment. A parametric analysis investigates the effect of the intermolecular particle force on the entrapment probability by varying the contact load, lubricant viscosity, elastic modulus of the contacting solids, contact velocity and the macroscopic (Coulomb) coefficient of friction.

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An Experimental Study of Surface Roughness Effects on Turbulent Boundary Layer Flow and Heat Transfer

10.21236/ada212099 ◽

1989 ◽

Cited By ~ 5

Author(s):

Hugh W. Coleman ◽

Robert P. Taylor ◽

M. H. Hosni ◽

Glenn B. Brown ◽

Philip H. Love

Keyword(s):

Heat Transfer ◽

Boundary Layer ◽

Experimental Study ◽

Surface Roughness ◽

Turbulent Boundary Layer ◽

Boundary Layer Flow ◽

Roughness Effects ◽

Flow And Heat Transfer ◽

Turbulent Boundary Layer Flow ◽

Layer Flow

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Measurement of surface roughness effects on conductivity in the terahertz regime with a high-Q quasi optical resonator

2011 Abstracts IEEE International Conference on Plasma Science ◽

10.1109/plasma.2011.5992894 ◽

2011 ◽

Author(s):

Benjamin B. Yang ◽

John H. Booske

Keyword(s):

Surface Roughness ◽

Optical Resonator ◽

Roughness Effects ◽

High Q

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The fourth Leeds-Lyon symposium on surface roughness effects on lubrication

Wear ◽

10.1016/0043-1648(77)90051-5 ◽

1977 ◽

Vol 43 (1) ◽

pp. 154

Keyword(s):

Surface Roughness ◽

Roughness Effects

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Surface roughness effects on the reinforcement of cement mortars through 3D printed metallic fibers

Composites Part B Engineering ◽

10.1016/j.compositesb.2016.05.055 ◽

2016 ◽

Vol 99 ◽

pp. 305-311 ◽

Cited By ~ 56

Author(s):

Ilenia Farina ◽

Francesco Fabbrocino ◽

Francesco Colangelo ◽

Luciano Feo ◽

Fernando Fraternali

Keyword(s):

Surface Roughness ◽

Roughness Effects ◽

Cement Mortars ◽

3D Printed ◽

Metallic Fibers

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Reactive Ion Etching Induced Surface Damage of Silicon Carbide

Materials Science Forum ◽

10.4028/www.scientific.net/msf.483-485.765 ◽

2005 ◽

Vol 483-485 ◽

pp. 765-768 ◽

Cited By ~ 3

Author(s):

Jun Hai Xia ◽

E. Rusli ◽

R. Gopalakrishnan ◽

S.F. Choy ◽

Chin Che Tin ◽

...

Keyword(s):

Surface Roughness ◽

Reactive Ion Etching ◽

Surface Damage ◽

Textured Surface ◽

Rf Power ◽

Power Devices ◽

Ion Etching ◽

Maximum Value ◽

Wide Range ◽

Coarse Surface

Reactive ion etching of SiC induced surface damage, e.g., micromasking effect induced coarse and textured surface, is one of the main concerns in the fabrication of SiC based power devices [1]. Based on CHF3 + O2 plasma, 4H-SiC was etched under a wide range of RF power. Extreme coarse and textured etched surfaces were observed under certain etching conditions. A super-linear relationship was found between the surface roughness and RF power when the latter was varied from 40 to 160 W. A further increase in the RF power to 200 W caused the surface roughness to drop abruptly from its maximum value of 182.4 nm to its minimum value of 1.3 nm. Auger electron spectroscopy (AES) results revealed that besides the Al micromasking effect, the carbon residue that formed a carbon-rich layer, could also play a significant role in affecting the surface roughness. Based on the AES results, an alternative explanation on the origin of the coarse surface is proposed.

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