Behaviour of n-alkanes confined between iron oxide surfaces at high pressure and shear rate: A nonequilibrium molecular dynamics study
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Accepted version
Author(s)
Restrepo, Sebastián Echeverri
van Eijk, Marcel CP
Ewen, James P
Type
Journal Article
Abstract
The behaviour of n-alkanes confined and sheared between iron oxide surfaces has been studied using nonequilibrium molecular dynamics simulations. The molecular extension, orientation, film structure, flow, and friction have been investigated for a range of n-alkane chain lengths under conditions representative of the elastohydrodynamic lubrication regime. At high pressure, the molecules show strong layering and long-range order, suggesting solid-like films. Conversely, high shear rates result in less elongated, layered, and ordered molecules; indicating more liquid-like films. Although Couette flow is usually observed for short n-alkanes, the flow is often non-linear for long n-alkanes. The friction coefficient increases logarithmically with shear rate, but the slope decreases with increasing pressure such that it becomes insensitive to shear rate for long n-alkanes.
Date Issued
2019-05-13
Date Acceptance
2019-05-05
Citation
Tribology International, 2019, 137, pp.420-432
ISSN
0301-679X
Publisher
Elsevier
Start Page
420
End Page
432
Journal / Book Title
Tribology International
Volume
137
Copyright Statement
© 2019 Elsevier Ltd. All rights reserved. This manuscript is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International Licence http://creativecommons.org/licenses/by-nc-nd/4.0/
Sponsor
Engineering & Physical Science Research Council (EPSRC)
Engineering and Physical Sciences Research Council
Grant Number
EP/P030211/1
Subjects
0913 Mechanical Engineering
Mechanical Engineering & Transports
Publication Status
Published
Date Publish Online
2019-05-13