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.
and Bair, S.
Normalized Ashurst-Hoover Scaling and a Comprehensive Viscosity Corelation for Compressed Liquids, Journal of Tribology-Transactions of the ASME
(Accessed December 2, 2023)