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Normalized Ashurst-Hoover Scaling and a Comprehensive Viscosity Corelation for Compressed Liquids



Arno R. Laesecke, Scott Bair


The recent move toward physics-based elastohydrodynamics promises to yield advances in understanding of the mechanisms of friction and film generation 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 which maps the viscosity of three widely different liquids onto a maser Stickel curve. The master curve can be represented by a combination of two expotential 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.
Journal of Tribology-Transactions of the ASME


EHL, elastohydrodynamics, high-pressure, high-temperature, rheology, viscosity


Laesecke, A. and Bair, S. (2012), Normalized Ashurst-Hoover Scaling and a Comprehensive Viscosity Corelation for Compressed Liquids, Journal of Tribology-Transactions of the ASME (Accessed June 19, 2024)


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Created March 6, 2012, Updated February 19, 2017