If two (or even more) non reactive but mutually soluble liquids are mixed, is the viscosity of resulting compound an additive value? If yes, is the contribution of each component fractional with respect to final viscosity?
Hi,
the equation above could be valid only in systems, in which the components have equal or very similar specific molar volumes. Otherwise, use volume fractions instead of molar ones. For miscible systems without pronounced interactions like hydrogen or ionic bonds the log-additivity rule should hold.
Hi,
I would recommend the book: Viswanath et al.: Viscosity of Liquids; Springer (2007).
In this book there a mentioned several different purposes. Maybe this information ist helpful for you.
One of the mentioned equations is: etamix = x1*eta1 + x2*eta2 + x1*x2*G12
x1 and x2 are molar fractions!
It seems, that for chemically similar liquids (benzene, toluene) the additional mixing-parameter G12 approaches Zero! Unfortunately, as far as I know, there is not theory existing for the prediction of G12. For real mixtures e.g. water-ethanol with the well known volume depression G12 ist a very complicated funktion of temperature and mole fraction. For the description of measured data the equation seems to be helpful.
maybe my contribution is helpful.
With kind regards
Franz Werner
Hi,
> as far as I know, there is not theory existing for the prediction of G12
This is absolutely right and the only thing you can do is to measure viscosity of mixtures. We do this for refrigerant (low molar mass) - oil (high molar mass) and coolants (containing alcohols, formiat, water, acetate, etc.) for more than 50 years (from -40 to 190 °C, up to 200 bar, and viscosities from 0.2 to 20,000 cP) and haven't found any prediction for the behaviour of the viscosity of the mixtures!
Sorry for the late replay. Hopefully it helps reducing the legend That somebody can predict the mixture viscosity with high accuracy. See also my presentation on measuring mixture data of R245fa - oil mixtures slide 22 for ideal and real behavior of densities. This is in fact much easier to calculate as mixture viscosity and it is not correct to be answered.
Kind regard
Steffen Feja.
Conference Paper Eignungsuntersuchungen und thermodynamisches Verhalten von K...
You may want to also check out Reid, Prausnitz and Poling who give a detailed summary of viscosity models for mixtures.
Suppose I have binary phase fluids (gas/brine) in the reservoir rock having saturations gas Sg and water Sw. Similarly, the viscosity of brine and gas are eta-w and eta-g.respect.
Can I use this formula = Sg*eta-g+Sw*eta-w to find the viscosity of fluid mixtures?
Please refer "A simple and accurate method of calculating viscosity of gaseous mixture by Thomas Davidson pub by Bureau of mines " use google search
I have been working on a similar situation. I found that the viscosity of the mixture might be additive but it is better to use volume fraction or mass fraction. Since viscosity is immensely affected by heavier components. Further, You can check my model which is a compositional viscosity model to predict mixture viscosity.
Article P-μ-T cubic equation of viscosity for hydrocarbons
Possibly, a crude model is u_mixed = 1 / (mf_1/u_f1(T) + (1-mf_1)/u_f2(T))
where u_mixed is the viscosity of the mixed fluid, mf_1 is the mass fraction of fluid no. 1, u_f1(T) is the viscosity of fluid no. 1 as a function of temperature and u_f2(T) is the viscosity of fluid no. 2 as a function of temperature.
We will check your and Mishras correlation in our new Project. Be excited.
Steffen Feja Fantastic, I hope it goes well for you and your research group.
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