Revisiting the ASME Pressure-Viscosity Report Using the Tait-Doolittle Correlations

The ASME Pressure-Viscosity Report was a seminal publication on high pressure-viscosity and density supervised by the ASME Research Committee on Lubrication, sponsored by dozens of industries, and undertaken by Harvard University using high-pressure equipment developed by Prof. P. W. Bridgman. The resulting measurements of the “Viscosity and Density of Over 40 Lubricating Fluids of Known Composition at Pressures to 150,000 psi (1034 MPa) and Temperatures to 425 °F (218.3 °C/491.5 K)” should have become an invaluable reference to tribologists around the world. The present work revisits that monumental effort to distill the results into an established equation of state using modern computer software. The authors used curve-fitting techniques to fit measured density and viscosity data to the parameters of the Tait-Doolittle equation for use in further tribological modeling. This information will help a new generation of engineers to model the piezoviscous properties of lubricant base-stocks in diverse tribological applications.

New Central Film Thickness Equation for Shear Thinning Lubricants in Elastohydrodynamic Lubricated Rolling/Sliding Point Contact Conditions

This paper offers central film thickness formula pertaining to shear-thinning lubricants under rolling/sliding point contact conditions. The shear-thinning behavior of the lubricants is modeled using Carreau viscosity equation and the piezo-viscous response employed herein is the free-volume based Doolittle equation in conjunction with Tait's equation of state for lubricant compressibility. The present formulation is based on reciprocal asymptotic isoviscous piezo-viscous coefficient as it is a more accurate measure of the high pressure piezo-viscous response of elastohydrodynamic lubricated (EHL) lubricants compared to the conventional pressure–viscosity coefficient. Comparisons between simulated, curve-fitted values, and experimental results validate both the employed numerical approach and rheological model.