A New free Volume Model for Dynamic Viscosity of Dense Fluids Versus Pressure and Temperature. Extension to a Predictive Model for not Very Associative Mixtures

Abstract

This article presents the extension of a viscosity model to mixtures. This model, based on the free volume concept, has been previously validated for pure dense components. This model involves three physical constants for each pure compound. If the viscosity is known at a reference pressure and temperature it is sufficient to use two constants per pure compound. The model has been adapted in order to obtain a predictive expression able to represent with accuracy the pressure-temperature variations of the dynamic viscosity of a mixture knowing only the characteristic parameters of each pure compound and the composition. The database used contains 3440 data points relative to 15 binaries, 4 ternaries and 1 system with more than three constituents. The model's results are also compared with those calculated from the very well-known Grunberg and Nissan's mixing law, and Katti and Chaudhri's mixing law.