Entropy Scaling of Viscosity—I: A Case Study of Propane

Abstract

In this work, a broadly applicable and simple approach for building high accuracy viscosity correlations is demonstrated for propane. The approach is based on the combination of a number of recent insights related to the use of residual entropy scaling, especially a new way of scaling the viscosity for consistency with the dilute-gas limit. With three adjustable parameters in the dense phase, the primary viscosity data for propane are predicted with a mean absolute relative deviation of 1.38%, and 95% of the primary data are predicted within a relative error band of less than 5%. The dimensionality of the dense-phase contribution is reduced from the conventional two-dimensional approach (temperature and density) to a one-dimensional correlation with residual entropy as the independent variable. The simplicity of the model formulation ensures smooth extrapolation behavior (barring errors in the equation of state itself). The approach proposed here should be applicable to a wide range of chemical species. The Supporting Information includes the relevant data in tabular form and a Python implementation of the model.

Excess-entropy scaling in supercooled binary mixtures

“…Rosenfeld found by applying appropriate dimensionless units that the viscosity and diffusion coefficient collapse to a univariate function of the excess entropy for single-component atomic liquids. Since then, excess-entropy scaling has been the focus of simulation and experimental studies in various contexts 18 – 39 , including atomic mixtures, molecular liquids, ionic liquids, network-forming liquids, nanoconfined liquids, nonlinear sheared liquids, and more. For a recent review of excess-entropy scaling, see ref.…”

Connecting Entropy Scaling and Density Scaling

“…The review of Dyre 1 in 2018 summarized the progress in this field up to that date. Since then, additional studies have considered the physical basis of this approach 2,7 , and applied the technique to different systems: the Lennard-Jones fluid 8 , refrigerants 9,10 , and alkanes 11,12 .…”

Dynamic Viscosity of Binary Fluid Mixtures: A Review Focusing on Asymmetric Mixtures

“…After introducing a modified approach with a dimensionless residual entropy per unit volume as the independent scaling variable and a suitable choice of a reference fluid for refrigerants [46], the approach was first applied to model fluids in conjunction with accurate Helmholtz-energy equations of state [47]. Subsequently, comprehensive studies on pure hydrocarbons were carried out by Bell [48,49]. First results for the calculation of viscosities in conjunction with Helmholtz-energy mixture equations of state were recently published by Binti Mohd Taib and Trusler [50], Mairhofer [51], and Yang et al [52].…”

“…Yang et al [52] focused on the representation of refrigerant mixtures. In contrast to Mairhofer [42], who applied the scaling as proposed by Novak [54], Yang et al [52] used the plus-scaled reduced residual viscosity according to Bell [48]. Results with respect to the correlation of Yang et al [52] are presented here for systems in which the fluid-specific scaling factor is available for each component.…”