[balajibabu]

I Have Drawn Combustor 3D Model Using Catia V5 and Please Guide Me How To Import and Mesh The File In Gambit.Thanks in advance for valuable suggestion.

[ershad]

hi
I am simulating a membrane bio-reactor. My reactor has 2 main volumes (Attached file). I subtracted smaller volume from the other, but I retained the subtracted volume.
I have defined 3 boundary conditions as follow:

1. Velocity Inlet (flow of air) : the lower face of smaller volume
2. Pressure outlet: the upper face of bigger volume: it is open to atmosphere.
3. ???I don't know how to define the boundary condition of the upper face of smaller volume. In reality the smaller volume is open from top and the air rise up in the smaller volume and goes out from top of it and enters the bigger volume, At initial, the reactor is full of water and its volume fraction is 1.
I have tried some boundary conditions for the upper face of smaller volume(face2), but I encountered ERRORS as follow:

1. OUTFLOW: "Warning both outflow and and pressure boundaries are present in the domain. This is an incompatibility and solution cannot proceed until this is fixed."

2. INTERIOR: "Error: Cannot change face2 to interior because there is only one adjacent cell thread."

3. INTERNAL: "Error: Cannot change face2 to interior because there is only one adjacent cell thread."

What can I define the boundary condition of that face?
Sincerely yours,
Ershad