Discussion Forum

Chengqi,

One solution is to divide the domain using "partition domain" in the "Geometry" node. Then apply the reaction to each subdomain that you want. Finally, run the simulation.
Don't forget to inspect the model one more time to make sure that your definitions of materials, boundary conditions, ... are not changed as a result of the geometry change.

Amin,

Hi, Amin,

Thanks for replying. I have two separate domains in my geometry, one for the porous media and the other for the free flow domain. I followed the method in the Carbon deposition example: first build a 0-D model (component 1)for the chemical reaction via "reaction engineering" interface and then create a time and space dependent model. In the time and space dependent model (component 2), there is a default "chemistry" interface but it occupies all the geometry. There is no settings to change it.

Chengqi

I contacted COMSOL support team for this question, and quote:

"The Chemistry physics will be applied to all domains by default. However,
this physics interface just stores information about the reaction kinetics
and does not actually indicate where the reactions are occurring.

Instead, the "Reaction Sources" node in Transport of Concentrated Species
is responsible for applying the reaction in the domain. In your case, it is
appropriately applied to domain 2 only which means that species will only
react in this selected domain."

Hope this helps who have the same question.

But my concern is that I checked the results and find that the reaction rate is non-zero beyond domain 2. I still do not know why.