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-   -   Working with mixture in CFX 5.7.1 (http://www.cfd-online.com/Forums/cfx/21075-working-mixture-cfx-5-7-1-a.html)

 Cesar Augusto March 12, 2005 14:06

Working with mixture in CFX 5.7.1

Hello:

I want to find a solution with a simple Tmixer that works with Ethanol and Water. These two materials are well known.

When I define the materials and the corresponding boundaries conditions (one inlet for Ethanol and the other for water, one outlet for the mixture) I think I have a problem.

First I defined only these two materials. Then I added a mixture containing the two materials. Only doing this I could work with diffusivity parameter, that I know it is important. But there are other parameters i can't manage well, like interface mass flux, length interface mixing, etc.

The results are not perfect. First off all because the mixing occurrs so fast, even something before the two materials contact each other.

Where might be my mistake???

 Phil March 15, 2005 14:06

Re: Working with mixture in CFX 5.7.1

It sounds like you've set up a multiphase calculation rather than a multicomponent calculation. A multiphase calculation has multiple materials in the 'Fluids List' for the domain, while a multicomponent problem chooses a single material which is a 'Variable Composition Mixture' of other materials. See the documentation for more details on how to set up multicomponent simulations.

 Cesar Augusto March 16, 2005 14:49

Re: Working with mixture in CFX 5.7.1

Dear Phil

I use a simulation where a mixture of variable composition is the only one material, composed by Ethanol and Water. For the Inlet 1 through Water come in, the mass fraction of Ethanol has a value of 0.0 and for the Inlet 2 through Ethanol come it has a value of 1.0. That's because in the fluids components of the domain only Ethanol appears, this is surely because Water component was constrained and Ethanol was given a diffusivity value (transport equation).

But when I run the simulation in CFX solver, almost immediately an error was found saying

ERROR #001100279 has occurred in subroutine ErrAction. | | Message: | | Option = Ideal Mixture is not currently supported

It is strange because in a previous simulation the Mixture material was defined as ideal mixture too and the running was OK.

Could you say something about my simulation and give me your comments and better suggestions how to solve the problem.

Thanks

Cesar A.

 Phil March 16, 2005 15:09

Re: Working with mixture in CFX 5.7.1

Sounds like you should contact your support rep.

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