Predicting the viscosity of n-alkane liquid mixtures based on molecular description
File(s)
Author(s)
Nguyen, T-B
Riesco, N
Vesovic, V
Type
Journal Article
Abstract
A new model has been developed to predict the viscosity of liquid, n-alkane mixtures. It represents a mixture by a single pseudo-component characterized by an appropriate molecular weight and calculates the viscosity by means of the modified, extended hard-sphere model (EHS) that makes use of an universal function relating reduced viscosity to reduced volume. For mixtures that contain n-alkanes with a similar number of carbon atoms, the molecular weight of the pseudo-component is simply given by the molecular weight of the mixture. For more asymmetric mixtures, the choice of the molecular weight is a function of the difference in the number of carbon atoms, between the longest and the shortest chain. The proposed model is a precursor of a new family of models that do not require the knowledge of detailed composition of the mixture, but still take advantage of the underlying molecular description. The developed model, named 1-component Extended Hard-Sphere (1-cEHS), predicted, in general, the viscosity of binary and multicomponent n-alkane mixtures with uncertainty of 5%, even when the mixtures contain very long n-alkanes. For highly asymmetric binary mixtures of alkanes the predictions deteriorated, but improved for highly asymmetric multicomponent mixtures indicating that the presence of the intermediate alkane species leads to a better prediction.
We have also tested two other viscosity models, the extended hard sphere (EHS) and Vesovic-Wakeham (VW), that also rely on kinetic theory to provide the molecular description, but require a full compositional specification of the mixture. They can also predict the viscosity within 5%, but the presence of the long chain n-alkanes in a mixture as well as the high asymmetry, leads to deterioration of the prediction.
We have also tested two other viscosity models, the extended hard sphere (EHS) and Vesovic-Wakeham (VW), that also rely on kinetic theory to provide the molecular description, but require a full compositional specification of the mixture. They can also predict the viscosity within 5%, but the presence of the long chain n-alkanes in a mixture as well as the high asymmetry, leads to deterioration of the prediction.
Date Issued
2017-11-15
Date Acceptance
2017-07-05
Citation
Fuel, 2017, 208 (1), pp.363-376
ISSN
1873-7153
Publisher
Elsevier
Start Page
363
End Page
376
Journal / Book Title
Fuel
Volume
208
Issue
1
Copyright Statement
© 2017 Elsevier Ltd. All rights reserved. This manuscript is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/
Sponsor
Qatar Shell Research and Technology Center QSTP LLC
Identifier
https://www.sciencedirect.com/science/article/pii/S0016236117308682
Grant Number
490000724
Subjects
Science & Technology
Technology
Energy & Fuels
Engineering, Chemical
Engineering
Alkanes
Hard-sphere theory
Liquid
Viscosity
Mixtures
POTENTIAL-ENERGY SURFACE
FLUID TRANSPORT-COEFFICIENTS
OCTANE PLUS DECANE
HARD-SPHERE MODEL
FRICTION THEORY
THERMOPHYSICAL PROPERTIES
VISCOMETRIC PROPERTIES
KINEMATIC VISCOSITIES
373.15 K
REFRACTIVE-INDEXES
0306 Physical Chemistry (incl. Structural)
0904 Chemical Engineering
0913 Mechanical Engineering
Energy
Publication Status
Published
Date Publish Online
2017-08-11