Modeling Alkane and Haloalkane Mixture Viscosities in a Three-Parameter Corresponding States Format

Abstract

The fundamental structure of the model is based upon a detailed and innovative conformality analysis of the viscosity surfaces of pure fluids similar to that proposed for thermodynamic properties [G. Scalabrin et al. Fluid Phase Equilib. 170:23 (2000); Int. J. Refrig. 26:35 (2003)], resulting in the introduction of a new specific scaling parameter ψ for viscosity, defined by a single experimental viscosity value. The model structure is based on two reference fluids for which pure-fluid viscosity dedicated equations (VDE) are available, which in this work are ethane and propane. The model is then extended to mixtures following the classical corresponding states (CS) one fluid model using mixing rules without interaction parameters. This gives the model a predictive character. It can be reliably applied in a wide range of pressure–temperature values, in both liquid and vapor phases, due to the validity ranges of the reference equations. The investigated mixtures include binary and multicomponent systems of both light and heavy n-alkanes and halogenated alkanes including R134a, R125, R152a, R143a, R22, R142b, R32, and R124 as components. For both families of fluids, the accuracy in terms of absolute average deviation (AAD) is within 2.68% in the vapor phase and 3.0% in the liquid phase. The model has also been validated for strongly azeotropic mixtures such as R32–R290 and R134a–R290 giving interesting results by fitting the interaction parameters on a limited subset of data. The effectiveness of the proposed procedure is enhanced by the comparison with a recently published advanced theoretical model.