Inclined cylinder, countercurrent-multiphase flow
 

Hi, I am working on a problem with countercurrent multiphase flow in an inclined cylinder.(Using air and sand). Sand enters from elevated side in a way that interface line makes 90 degree angle at centre of the circular inlet section. Both air and sand have constant mass flow rates as their respective inlet conditions and other properties.
In figure attached, face 5 is the interface. Sand is below this face and air on above. So far both inner circular face and arc face are disconnected. What more needs to be done here(except meshing,inclination and zone assignement). OR I shouldnt make sand zone at all? If its OK here then how to active those interfaces.

Here is the isometric view of the geometry in Gambit.

We can help you in meshing, but if you want to know about multiphase, please post question here http://www.cfd-online.com/Forums/fluent-multiphase/

Thanks for the reply, I will post it there.

Can u tell me about the geometry. Is there something that needs to be changed.

why are you using interface?
Interface in the sense of Gambit, isn't an interface in the sense of "multiphase"
if you only want to separate air from sand, then you can reconnect your faces, and delete the interface-bc.
Just define 2 fluid domains, one for air and one for sand

I did as you explained, I have few questions,
(1) Does air domain includes sand domain portion as well or just the upper portion. If it does not then, I will have to subtract the sand portion from air one.
(2)If it does, then while meshing, do I have to mesh them separately or just the air domain.
(3)If I have to do it separately then I guess Gambit part is over.

if face 5 is the planar one, then you need to split your inner cylinder with your face 5. It will give you 2 volumes: one above face 5 and one below.
Assign the one below for air, and the other for sand.
Fluent will just use both fluid domains for initializing vof.

From my side you don't need the ring volume (if it is a solid part)

That means there will be two faces instead of one single face 5. One will belong to air zone and other to sand zone. While assigning boundary conditions there will be two faces then. Problematic?
Solid volume can be removed but both air and sand are inside one cylinder. Sand will be flowing over a surface. As I splitted both zones at face 5, some surface has to cover sand portion. Am I thinking right?

No, you only have one surface (named face 5) Split your inner cylinder with this surface. It will separate your cylinder into 2 subvolumes.
Don't care about BC on this surface, Gambit will treat it as interior, and your sand will be able to "flow" over this surface.
This separation will just be needed for vof initialization

I think, I have corrected the geometry with mentioned changes. Please check my settings in VOF model and I have posted it in fluent multiphase forum here:
http://www.cfd-online.com/Forums/flu...hase-flow.html