Residual entropy model for predicting the viscosities of dense fluid mixtures
File(s)Entropy Scaling - acceted version.pdf (521.29 KB)
Accepted version
Author(s)
Binti Mohd Taib, M
Trusler, JPM
Type
Journal Article
Abstract
In this work, we have investigated the mono-variant relationship between the reduced viscosity and residual entropy in pure fluids and in binary mixtures of hydrocarbons and hydrocarbons with dissolved carbon dioxide. The mixtures considered were octane + dodecane, decane + carbon dioxide, and 1,3-dimethylbenzene (m-xylene) + carbon dioxide. The reduced viscosity was calculated according to the definition of Bell, while the residual entropy was calculated from accurate multi-parameter Helmholtz-energy equations of state and, for mixtures, the multi-fluid Helmholtz energy approximation. The mono-variant dependence of reduced viscosity upon residual molar entropy was observed for the pure fluids investigated, and by incorporating two scaling factors (one for reduced viscosity and the other for residual molar entropy), the data were represented by a single universal curve. To apply this method to mixtures, the scaling factors were determined from a mole-fraction weighted sum of the pure-component values. This simple model was found to work well for the systems investigated. The average absolute relative deviation (AARD) was observed to be between 1% and 2% for pure components and a mixture of similar hydrocarbons. Larger deviations, with AARDs of up to 15%, were observed for the asymmetric mixtures, but this compares favorably with other methods for predicting the viscosity of such systems. We conclude that the residual-entropy concept can be used to estimate the viscosity of mixtures of similar molecules with high reliability and that it offers a useful engineering approximation even for asymmetric mixtures.
Date Issued
2020-04-30
Online Publication Date
2020-04-23T10:34:37Z
Date Acceptance
2020-04-02
ISSN
0021-9606
Publisher
AIP Publishing
Start Page
164104
End Page
164104
Journal / Book Title
The Journal of Chemical Physics
Volume
152
Issue
16
Copyright Statement
© 2020 Author(s).
Identifier
https://aip.scitation.org/doi/10.1063/5.0002242
Subjects
02 Physical Sciences
03 Chemical Sciences
09 Engineering
Chemical Physics
Publication Status
Published
Date Publish Online
2020-04-22