Publication detail
The Shear-Thinning Elastohydrodynamic Film Thickness of a Two-Component Mixture
LIU, Y. WANG, G.J. KŘUPKA, I. HARTL, M. BAIR, S.
Czech title
Utváření mazacích filmů u nenewtonovských maziv
English title
The Shear-Thinning Elastohydrodynamic Film Thickness of a Two-Component Mixture
Type
journal article - other
Language
en
Original abstract
Lubricant base oils are often blends of different molecular weight cuts to arrive at a specified ambient pressure viscosity and, to improve the temperature-viscosity behavior or to simply increase the viscosity, viscosity-modifying polymer additives are often added to the base oil. This paper investigates the effect of mixture rheology on EHL film thickness using EHL contact measurements and a full numerical analysis for three synthetic lubricants including two single-component lubricants PAO650, and PAO100 and a mixture of these. The pressure and shear dependences of the viscosity of these lubricants were measured with high-pressure viscometers; viscosities were not adjusted to fit experiment. The point contact film thicknesses for these lubricants in pure rolling were measured using a thin-film colorimetric interferometry apparatus. Numerical simulations based on the measured rheology show very good agreement with the measurements of film thickness while the Newtonian prediction is up to twice the measurement. These results validate the use of realistic shear-thinning and pressure-viscosity models which originate from viscosity measurements. It is conceivable that simulation may provide a means to "engineer" lubricants with the optimum balance of film-thickness and friction though intelligent mixing of components.
Czech abstract
Článek shrnuje výsledky teoretického řešení a experimentálního studia problematiky utváření mazacích filmů při užití nenewtonovských maziv.
English abstract
Lubricant base oils are often blends of different molecular weight cuts to arrive at a specified ambient pressure viscosity and, to improve the temperature-viscosity behavior or to simply increase the viscosity, viscosity-modifying polymer additives are often added to the base oil. This paper investigates the effect of mixture rheology on EHL film thickness using EHL contact measurements and a full numerical analysis for three synthetic lubricants including two single-component lubricants PAO650, and PAO100 and a mixture of these. The pressure and shear dependences of the viscosity of these lubricants were measured with high-pressure viscometers; viscosities were not adjusted to fit experiment. The point contact film thicknesses for these lubricants in pure rolling were measured using a thin-film colorimetric interferometry apparatus. Numerical simulations based on the measured rheology show very good agreement with the measurements of film thickness while the Newtonian prediction is up to twice the measurement. These results validate the use of realistic shear-thinning and pressure-viscosity models which originate from viscosity measurements. It is conceivable that simulation may provide a means to "engineer" lubricants with the optimum balance of film-thickness and friction though intelligent mixing of components.
Keywords in Czech
EHL; reologie; tloušťka mazacího filmu
Keywords in English
EHL; elastohydrodynamics; rheology; film thickness; shear-thinning; non-Newtonian; viscosity
RIV year
2008
Released
17.04.2008
Publisher
ASME
Location
USA
ISSN
0742-4787
Journal
ASME Transaction, Journal of Tribology
Volume
130
Number
2
Pages from–to
021502-1–021502-7
Pages count
7
BIBTEX
@article{BUT44742,
author="Ivan {Křupka} and Martin {Hartl},
title="The Shear-Thinning Elastohydrodynamic Film Thickness of a Two-Component Mixture",
journal="ASME Transaction, Journal of Tribology",
year="2008",
volume="130",
number="2",
month="April",
pages="021502-1--021502-7",
publisher="ASME ",
address="USA",
issn="0742-4787"
}