'Exhaust Type' Volume Mesh Problem
 

To anyone that can help,

I am trying to volume mesh a gas flow through an exhaust type system with one inlet and several outlets, into atmospheric conditions. The aim is to use streamlines to find the resulting effects.

Before I get bombarded with questions here is what I have already tried;

1 region for all the parts, which includes a velocity inlet into the system and a pressure outlet at the end of the system within a confined area. Surface Mesh has already been generated, along with a leak detection test. Surface Mesh has already been enhanced to get required accuracy on specific surfaces. The surface mesh only consists of the surface wrapper. To generate the volume mesh the Surface Wrapper, Surface Remesher, Polyhedral Mesher, Prism Layer Mesher model are selected.

2 regions; 1 for the enclosed pipe flow and one for the atmospheric conditions which is separated by creating an interface between the regions at the pressure outlets. Separate meshes have been generated for each region as seen above.

Overset Mesh overlapping two regions. The overset mesh incorporates the parts as one region overlapping atmospheric conditions in the second region. same process has been used as above.

Every time I come to generate a volume mesh it gives me an error message;

'region not manifold'
'surface not closed'
'baffle not closed'

Any suggestions or techniques that other have used for similar problems would be greatly appreciated.

PWeller