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richard ben May 13, 2013 12:43

What's is mixing law
Hi everyone,

I am doing species transport simulation and have no idea some theory in fluent.

What's is mixing law, mass weighted mixing law, ideal gas mixing law and kinetic theory?

For example, to calculate the heat capacity of the mixture,

I guess the mixing law is based on the molar fraction of each species

and the mass weighted mixing law is based on the mass fraction.

Is this correct? and what is ideal gas mixing law?

I will appreciate it a lot for your reply.

A CFD free user May 13, 2013 13:22

All these are some generic laws to define thermodynamic properties for a mixture which are usually function of molar fraction, temperature and some other parameters. I think you can find more details in Fluent user guide. But if you don't, have a look at thermodynamics book regarding ideal and non-ideal solutions. Mixing laws are very important concept in solutions thermodynamic.

Liufeng_ustb May 14, 2013 02:52

Hi, Azarafza.
I have a question.
Do you know some source for looking for some thermodynamic data and physical properties of material?
In particular, for FLUENT, we sometimes need to define L-J Characteristic Length and L-J energy, where should we go to look for these?
Expect your answer.
Best wishes

A CFD free user May 14, 2013 08:05

Hi, Liufeng
Well, I just rant into them (L-J charachteristic length and energy) in my advanced thermodynamic course, I suppose you can find more info in textbooks such as
Molecular Thermodynamics of fluid phase Equilibria(prausnitz-1999)
or on solid state physics or kinetic theory of gases such as Introduction to Solid State Physics, 5-th edition, John Willey & Sons Ltd., 1976 or even software database such as CHEMKIN or maybe Aspen. But I haven't tried that before.
Hope it helps

richard ben September 25, 2014 17:30

Hi Azarafza,

Thanks for your reply although it is way to late.


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