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Mesh interfaces and reactions in porous media - why not working?

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Old   December 15, 2013, 06:40
Default Mesh interfaces and reactions in porous media - why not working?
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Hi all,

When I use the mesh provided with fluent for the porous media tutorial (~car exhaust with a porous catalyst section) and setup my simulation I can get oxidation (and heat generation) to occur in the porous media as desired. When I use my own meshes with an identical setup I can't get any oxidation or heat generation to occur. Well, it works if I make a mesh that is air->porous coal but not if I make a mesh that is air->porous coal -> air. I get fluid flow but not any oxidation, even when I set the inflow temperature to be above the autoignition temperature.

I'm using the built in meshing software in Fluent simulation modules in ANSYS Workbench.

I've noticed that for the tutorial's mesh and my own air->porous coal mesh, there are no mesh interfaces in the setup section in Fluent. That is, the section is greyed out.

Current meshing method:
all cells are 1mm^3 cubes.
each air or porous region is a simple cubic or rectangular shape.
hard sizing used for the entire mesh.
hard sizing set at the interface walls on both sides.
the wall of each side of the interface is being named in meshing.
the named walls on each side of each interface are being converted to interface type in Fluent and then joined up and named in the interfaces section.


Some general notes on the setup of the simulation:
inflow speed ~0.1m/s of pure oxygen (I used the mesh region name "air" above instead of pure oxygen) at around 313K
laminar flow model being used
reactions are only turned on in the porous section

But like I said, the simulation works fine for the two meshes mentioned above but not for any that I create that are closer to the setup I want.

Any ideas?
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