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Old   January 14, 2020, 10:05
Default Full porous model
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What is the difference between adding a solid material in solid definitions and not adding it when using the Full Porous Model? So far, I've done simulations that have mass transfer between my multi component phase and the solid, but I didn't used any material in solid definition. If I want to add a material the settings asks for fluid solid area density (which I don't know how to calculate). So I'm wondering what does CFX "understand" when we add a material and when we don't.

In addition, when I add a source term to mass fraction, the equation is similar to the ones defined for Additional Variable?

Thanks in advance
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Old   January 14, 2020, 11:02
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A porous model is understood in ANSYS CFX as a fluid moving through a solid matrix.

If there is physics interaction between fluid and the solid beyond just the drag/friction, you must specify which physics you want to model in the solid matrix.

Not certain what physics you have modeled using a multicomponent approach, but certainly not between the solid matrix and the fluid since a multi-component approach cannot model the relative velocity between the fluid and the solid.
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Old   January 15, 2020, 08:19
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Quote:
Originally Posted by Opaque View Post
A porous model is understood in ANSYS CFX as a fluid moving through a solid matrix.

If there is physics interaction between fluid and the solid beyond just the drag/friction, you must specify which physics you want to model in the solid matrix.

Not certain what physics you have modeled using a multicomponent approach, but certainly not between the solid matrix and the fluid since a multi-component approach cannot model the relative velocity between the fluid and the solid.
The porous zone adsorbes one of the components of my multicomponent fluid. In other post I've asked if CFX considers the porous zone as phase, hence, im my case, a multiphase and multicomponent problem. The answer was that CFX does not consider the porous zone as a phase. I'm wondering if I add a material to the solid definition CFX will start to consider a multiphase problem.
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Old   January 15, 2020, 08:30
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ANSYS CFX full porous model implementation is fundamentally a multi-phase implementation where

1 - the velocity field is algebraically imposed (mostly stationary)

2 - the volume fraction is also fixed

3 - forces between the fluid and the solid are represented by the resistance model.

Keep in mind that any component removed from the fluid mixture does not go into the solid matrix by any means UNLESS you are modeling the solid phase explicitly

Please have a closer look at the documentation, and how the equations are formulated to understand the models. You can also compare the literature about full porous models obtained from the "volume averaging approach" and you can then make your own conclusions.

At the end, what matters is that you got a "porous model" framework to customize for your specific needs. Every porous model is different depending on your application. There are some that are well established because they represent common use cases.
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Old   March 15, 2020, 20:10
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Quote:
Originally Posted by Opaque View Post
ANSYS CFX full porous model implementation is fundamentally a multi-phase implementation where

1 - the velocity field is algebraically imposed (mostly stationary)

2 - the volume fraction is also fixed

3 - forces between the fluid and the solid are represented by the resistance model.

Keep in mind that any component removed from the fluid mixture does not go into the solid matrix by any means UNLESS you are modeling the solid phase explicitly

Please have a closer look at the documentation, and how the equations are formulated to understand the models. You can also compare the literature about full porous models obtained from the "volume averaging approach" and you can then make your own conclusions.

At the end, what matters is that you got a "porous model" framework to customize for your specific needs. Every porous model is different depending on your application. There are some that are well established because they represent common use cases.
Very fine answer. It helped me a lot! Thank you very much.
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