Predictive Corresponding-States Viscosity Model for the Entire Fluid Region: n-Alkanes

Abstract

Previous work by the author demonstrated a novel approach for correlating the scaled self-diffusion coefficient, viscosity, and thermal conductivity with the residual entropy over the entire fluid region. It is shown here that a new entity-based scaled viscosity model correlates pure n-alkane components to a single semilogarithmic line with the entity residual entropy. With five fitting parameters, a 5.2% group average of the absolute relative deviations (AADs) is obtained over the entire fluid region for a group of 17 n-alkanes, ranging from methane to linear polyethylene with a molecular weight of 1280 g/mol. It was also found that these same five fitting parameters predict the fluid viscosity of some other alkanes, ethers, and olefins. Thus, the entity-based scaling approach introduced here provides a predictive corresponding-states model for fluid viscosity of nonassociating molecules and is a practical approach to determining viscosity in process engineering, product engineering, oil and gas reservoir engineering, pipelines, and fracking applications. This entity-based scaled viscosity-entity residual entropy model is particularly useful in the critical region and at high pressures because the traditional saturated liquid and saturated vapor viscosity component correlations are not applicable.