Viscosity ratio effect in the emulsion lubrication of soft EHL contact

de Vicente, J., Spikes, H. A. and Stokes, J. R. (2006) Viscosity ratio effect in the emulsion lubrication of soft EHL contact. Journal of Tribology, 128 4: 795-800. doi:10.1115/1.2345400

Author de Vicente, J.
Spikes, H. A.
Stokes, J. R.
Title Viscosity ratio effect in the emulsion lubrication of soft EHL contact
Journal name Journal of Tribology   Check publisher's open access policy
ISSN 0742-4787
Publication date 2006-01-01
Year available 2006
Sub-type Article (original research)
DOI 10.1115/1.2345400
Open Access Status DOI
Volume 128
Issue 4
Start page 795
End page 800
Total pages 6
Place of publication New York
Publisher American Society of Mechanical Engineers
Language eng
Subject 09 Engineering
Abstract Many foodstuffs and personal care products consist of two-phase systems which, during use, are rubbed between compliant biosurfaces to form thin lubricating films. It is important to understand the nature and properties of the films thus formed since these contribute to the user's sensory perception, and thus appreciation, of the products concerned. In this paper, the lubrication properties of simple oil-in-aqueous phase emulsions are studied in a steel/elastomer "soft-EHL" contact. It is found that overall behavior is strongly dependent on the ratio of the viscosities of the two phases. When the viscosity of the dispersed oil phase is lower or comparable to that of the continuous aqueous phase, the latter enters the contact and controls,film formation and friction. However when the dispersed phase has viscosity at least four times larger than the dispersion medium, the former enters the contact and determines its tribological properties. This effect is believed occur because at high viscosity ratios the droplets are nondeformable and are thus forced into the contact inlet region, where collisions occur that result in shear-induced coalescence. Once a pool of viscous fluid is formed, the lower viscosity bulk fluid is unable to displace it because the viscous shear stress is too small, so the pool acts as a reservoir to supply the contact.
Keyword Engineering, Mechanical
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collections: Excellence in Research Australia (ERA) - Collection
School of Chemical Engineering Publications
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Created: Thu, 02 Jul 2009, 02:04:04 EST