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How to define the mass diffusion coefficients of species?

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Old   April 21, 2009, 11:37
Default How to define the mass diffusion coefficients of species?
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Yang Xiaoguang
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My model is about the diffusion of multicomponents in porous media. I want to modify the mass diffusion coefficients including the effects of porosity and tuotorsity so I need to define the mass diffusion coefficients of each species separately, so how can I make it?
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Old   May 10, 2009, 17:29
Lightbulb
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Quote:
Originally Posted by legendyxg View Post
My model is about the diffusion of multicomponents in porous media. I want to modify the mass diffusion coefficients including the effects of porosity and tuotorsity so I need to define the mass diffusion coefficients of each species separately, so how can I make it?
Hi, I think you are modeling fuel cells. You can use define_diffusivity macro, in this way you can define only Dim (i.e, dffusivity of species i in mixture). Another issue in fuel cell electrodes, you cannot specify different porosity tortuosity correction for different directions.

I am also working on modeling of fuel cells but I could not find a proper way to incorporate "full" multicomponent diffusion in porous electrodes in a fuel cell. Also, I could not solve direction dependent porosity corrections issue, yet.

good luck to you
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