Predicting the viscosity of liquid refrigerant blends: comparison with experimental data

Royal, D.D.; Vesovic, Velisa; Trusler, J. P. Martin; Wakeham, W. A.

doi:10.1016/j.ijrefrig.2004.09.007

Cited by 9 publications

(4 citation statements)

References 26 publications

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“…Moreover, the available experimental data often covers a rather limited range of pressure, temperature, and composition. Different approaches to predict transport properties are currently used and further developed, e.g., corresponding states principles, − Friction Theory, , Free Volume Theory, − Thermodynamic Scaling, − Isomorph Theory, − or, based on the kinetic theory, the Vesovic-Wakeham approaches. − Specifically, entropy scaling and Isomorph Theory (which incorporates both “entropy scaling” and “thermodynamic scaling” in a more general framework) provide the potential of covering a very wide range of pressure and temperature in a simple and reliable manner.…”

Section: Introductionmentioning

confidence: 99%

Pure Substance and Mixture Viscosities Based on Entropy Scaling and an Analytic Equation of State

Lötgering-Lin

Fischer

Hopp

et al. 2018

Ind. Eng. Chem. Res.

149

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This study proposes a simple model for viscosities, based on entropy scaling, for real substances and mixtures. The residual entropy is calculated with the perturbed chain polar statistical associating fluid theory (PCP-SAFT). The model requires two or three pure component parameters, noting, however, that an entirely predictive group contribution approach as proposed in our previous work [Loetgering-Lin O.; Gross J. Ind. Eng. Chem. Res. 2015, 54, 7942−7952] gives also very good results. Overall, 140 real substances are considered with relative mean deviations from experimental data of about 5% (without excluding "outliers"). We performed molecular simulations for mixtures of simple model fluid in order to determine a suitable mixture model. A completely predictive approach for viscosities of real mixtures is thereby obtained. The model is evaluated for 566 mixtures with about 34,500 experimental data points of various complexity (i.e., nearly ideal systems as well as highly asymmetric mixtures). Mixtures of nonpolar substances and mixtures with at least one polar, but nonhydrogen-bonding component, are predicted very accurately with relative mean deviations of on average 6.2% (173 mixtures considered) and 5.3% (126 mixtures considered), respectively. Limitations of the model are found for mixtures with hydrogen-bonding (associating) components such as amines and alcohols, where deviations are systematically higher. Lastly, we present results of mixture viscosities using the purely predictive group contribution framework and find similar results for the predictive approach.

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Section: Introductionmentioning

confidence: 99%

Pure Substance and Mixture Viscosities Based on Entropy Scaling and an Analytic Equation of State

Lötgering-Lin

Fischer

Hopp

et al. 2018

Ind. Eng. Chem. Res.

149

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show abstract

“…There are number of ways of modifying the Enskog expressions in order to predict the behaviour of real fluids. 14 In our current work we focus on the solution successfully used as part of the VW method [26][27][28][29] and extend the VW method to mixtures modelled as chains formed from hard segments.…”

Section: The Vw Methods For Chain Moleculesmentioning

confidence: 99%

“…This choice of effective parameters is at the heart of the development of the VW method 26,27 that can be used to predict accurately the viscosity of a variety of different mixtures, including natural gas, 28 refrigerant, 29 and supercritical fluid mixtures. 26,27 The accuracy can be retained when predicting the viscosity of liquid mixtures 27,29 providing the systems contain molecules of similar molecular mass and size, thus allowing for a representation of each molecule by an effective hard sphere. If the molecules are different in size the hard-sphere representation is no longer adequate and a chain representation becomes more appropriate, if the accuracy is to be retained.…”

Section: Introductionmentioning

confidence: 99%

Viscosity of liquid mixtures: The Vesovic-Wakeham method for chain molecules

Wijn

Riesco

Jackson

et al. 2012

The Journal of Chemical Physics

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New expressions for the viscosity of liquid mixtures, consisting of chain-like molecules, are derived by means of Enskog-type analysis. The molecules of the fluid are modelled as chains of equally sized, tangentially joined, and rigid spheres. It is assumed that the collision dynamics in such a fluid can be approximated by instantaneous collisions. We determine the molecular size parameters from the viscosity of each pure species and show how the different effective parameters can be evaluated by extending the Vesovic-Wakeham (VW) method. We propose and implement a number of thermodynamically consistent mixing rules, taking advantage of SAFT-type analysis, in order to develop the VW method for chain molecules. The predictions of the VW-chain model have been compared in the first instance with experimental viscosity data for octane-dodecane and methane-decane mixtures, thus, illustrating that the resulting VW-chain model is capable of accurately representing the viscosity of real liquid mixtures.

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“…(7) and also the radial distribution function. To calculate the variables A * ij and α ij , one can use the following relations [33,34] …”

Section: The Viscositymentioning

confidence: 99%

Viscosity of Lennard–Jones fluid: Integral equation method

Khordad

2008

Physica A: Statistical Mechanics and its Applications

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Predicting the viscosity of liquid refrigerant blends: comparison with experimental data

Cited by 9 publications

References 26 publications

Pure Substance and Mixture Viscosities Based on Entropy Scaling and an Analytic Equation of State

Pure Substance and Mixture Viscosities Based on Entropy Scaling and an Analytic Equation of State

Viscosity of liquid mixtures: The Vesovic-Wakeham method for chain molecules

Viscosity of Lennard–Jones fluid: Integral equation method

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