Journal ArticleDOI
Normalized Ashurst-Hoover Scaling and a Comprehensive Viscosity Correlation for Compressed Liquids
Scott Bair,Arno Laesecke +1 more
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TLDR
In this paper, the authors normalized the Ashurst-Hoover scaling for thermal elastohydrodynamic simulation and mapped the viscosity of three widely different liquids onto a master Stickel curve, represented by a combination of two exponential power law terms.Abstract:
The recent move toward physics-based elastohydrodynamics promises to yield advances in the understanding of the mechanisms of friction and film generation that were not possible a few years ago. However, the accurate correlation of the low-shear viscosity with temperature and pressure is an essential requirement. The Ashurst-Hoover thermodynamic scaling, which has been useful for thermal elastohydrodynamic simulation, is normalized here in a manner that maps the viscosity of three widely different liquids onto a master Stickel curve. The master curve can be represented by a combination of two exponential power law terms. These may be seen as expressions of different molecular interaction mechanisms similar to the two free-volume models of Batschinski-Hildebrand and Doolittle, respectively. The new correlation promises to yield more reasonable extrapolations to extreme conditions of temperature and pressure than free-volume models, and it removes the singularity that has prevented wide acceptance of free-volume models in numerical simulations. [DOI: 10.1115/1.4005374]read more
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An improved Yasutomi correlation for viscosity at high pressure
TL;DR: The Yasutomi temperature-pressure-viscosity correlation is attractive for elastohydrodynamic lubrication analysis because it does not require an equation of state for the liquid as mentioned in this paper.
Journal ArticleDOI
Lubrication properties of polyalphaolefin and polysiloxane lubricants: Molecular structure-tribology relationships
TL;DR: In this article, the rheological properties, elastohydrodynamic film thickness, and friction coefficients of several commercially available polyalphaolefin (PAO) and polydimethylsiloxane (PDMS)-based lubricants were investigated to assess relationships between molecular structure and lubricant performance.
Journal ArticleDOI
Viscosity models for pure hydrocarbons at extreme conditions: A review and comparative study
TL;DR: In this paper, the performance of seven select viscosity models, representative of various predictive and correlative approaches, is discussed and evaluated by comparison to experimental data of 52 pure hydrocarbons including straight-chain alkanes, branched alkane, cycloalkanes, and aromatics.
Journal ArticleDOI
Viscosity measurements for squalane at high pressures to 350 MPa from T = (293.15 to 363.15) K
María J. P. Comuñas,Xavier Paredes,Félix M. Gaciño,Josefa Fernández,Jean-Patrick Bazile,Christian Boned,Jean-Luc Daridon,Guillaume Galliero,Jérôme Pauly,Kenneth R. Harris +9 more
TL;DR: In this paper, the experimental high pressure viscosities for squalane (176 data points obtained for temperatures (293.15 to 363.15) K, at pressures up to 350 MPa with a maximum viscosity of 745 mPa · s) were determined with four different falling body viscometers as well as a quartz crystal resonator viscometer.
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Pressure dependence on the viscosities of 1-butyl-2,3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide and two tris(pentafluoroethyl)trifluorophosphate based ionic liquids: New measurements and modelling
TL;DR: In this paper, the experimental viscosity values for three ionic liquids, 1-butyl-2,3-dimethylimidazolium tris(pentafluoroethyl)trifluorophosphate, 1-(2-methoxyethyl)-1-methyl-pyrrolidinium trifluoro methyl) tri-polyethyl triplosophate and 1- butyl 2,3dimethylamidazolate bis(triffluoromethylsulfonyl)imide
References
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