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CCarl January 31, 2013 08:08

Dynamic mesh and boundary layer
 
Hi all,

I am working on flow in a tubular reactor. Besides some gas phase reactions, coke formation on the tube wall occurs. This makes that a solid layer grows on the tube inner wall over time. The mesh is hex and has a boundary layer at the gas/cokes interface as the flow is highly turbulent.

To model the coke layer growth, I am using the dynamic meshing model with a UDF (DEFINE_GRID_MOTION) that describes the cokes growth as function of local temperature and gas phase chemical concentrations. I am using the 'layering' option in dynamic meshing.

However as the coke layer grows, the fine boundary layer cells near the wall disappear and the larger cells that were originally in the middle of the tube get adjacent to the wall/gas interface. This makes that the y+ values are too high and eventually after some time steps the simulation diverges.

Does anybody have experience in dynamic meshing with an expanding solid region where you want to keep the boundary layer near the solid/gas interface? All tips and tricks are welcome!

Carl

phanh August 9, 2013 02:39

Quote:

Originally Posted by CCarl (Post 405273)
Hi all,

I am working on flow in a tubular reactor. Besides some gas phase reactions, coke formation on the tube wall occurs. This makes that a solid layer grows on the tube inner wall over time. The mesh is hex and has a boundary layer at the gas/cokes interface as the flow is highly turbulent.

To model the coke layer growth, I am using the dynamic meshing model with a UDF (DEFINE_GRID_MOTION) that describes the cokes growth as function of local temperature and gas phase chemical concentrations. I am using the 'layering' option in dynamic meshing.

However as the coke layer grows, the fine boundary layer cells near the wall disappear and the larger cells that were originally in the middle of the tube get adjacent to the wall/gas interface. This makes that the y+ values are too high and eventually after some time steps the simulation diverges.

Does anybody have experience in dynamic meshing with an expanding solid region where you want to keep the boundary layer near the solid/gas interface? All tips and tricks are welcome!

Carl

Hi,

Have you solved your situation? I have the same problem, but I do not know how to do it. Could you give me some tips?

Thanks


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