simulating a grain storage bin
 

Hello,
I would like to perform an aeration simulation of grain in a bin but I am not sure on the solver(s) that would work for me.
I have been using OpenFOAM-5.x. I made a simple silo (cylinder with a cone on top) in gmsh. I labeled the surfaces of the silo (bottom, top, sidewalls, conewalls). I also labeled the two volumes grain (the cylinder portion), and air (the cone portion). I believe I need to do this for porousSimpleFoam and the rhoPorousSimpleFoam solvers (should only need porousSimpleFoam as I should be able to assume incompressible flow). If I understand things correctly, I could also use fvmOptions and add a porous region with differing solvers. Is there a way to add this a different way? Like would I be able to "cut" this porous region to add a box in the middle of the porous region?

Is it "right" to have the porous region touching the inlet of the simulation? I have been playing with the pimpleFOAM porous blockage simulation and very weird things happen when the "porous" region touches the boundaries but this is what happens in a grain silo.

I also want to track the moisture content in the grain. Can this be done via a species or is there a ready built solver that couples moisture and temperature?

Using the gmsh to openFoam utility, I get a defaultFaces patch/wall. How can I remove this as it is not a "real" face, or what boundary conditions are needed? This defaultFace is located between the "grain" and "air" volumes.

Any and all help would be appreciated. I can also supply my test case if that can be beneficial.