Reply to “Comment on ‘New Experimental Data and Reference Models for the Viscosity and Density of Squalane’”

Abstract

The authors would like to thank Professor Bair for his insightful comments on ultrahigh-pressure viscosities. The viscosity model used by Schmidt et al. was a Tait-like2,3 model that has been shown to correlate accurately the viscosity of many fluids in the original investigation’s pressure range (0.1–275.8 MPa (40000 psi)) of interest. The upper pressure is indicative of the high pressures found in the petroleum industry4. However, after discussions with Professor Bair, it became clear a reference model that can accurately model the viscosity of squalane at ultrahigh-pressures is of interest to those working in the area of tribology.

Temperature and Pressure Dependence of the Viscosities of Krytox GPL102 Oil and Di(pentaerythritol) Hexa(isononanoate)

“…The first, the perfluoropolyether oil, Krytox GPL102 is the subject of a round-robin comparison of high pressure viscosity measurements on a specific sample being made by a group of laboratories worldwide employing a variety of viscometric techniques. The need for high-temperature, high-pressure viscosity reference materials to complement existing reference materials (water, toluene, cyclopentane, diisodecyl phthalate, and squalane − ) was identified at an annual meeting of the International Association for Transport Properties in 2009 (Table shows the range of applicability of the water standard and the other reference materials) and a subsequent workshop sponsored by Schlumberger Ltd. and Cambridge Viscosity in 2010 . This has resulted in an IUPAC project, “International Standard for Viscosity at Temperatures up to 473 K and Pressures below 200 MPa”, of which the round-robin measurements on Krytox GPL102 are part .…”

A Modeling Framework for Predicting and Correlating Viscosities of Liquids in Wide Range of Conditions

“…Quantitative correlation of liquid viscosities in wide range of conditions may present difficulties even for the multiparameter reference correlations. − Consequently, predicting these data is an exceptionally challenging task. The phase diagrams of viscosities are much more sophisticated in comparison to equilibrium thermodynamic properties such as densities or sound velocities.…”