Meshing cooling coils

Eric R.

Hello Gambit/Fluent users:

I created 3-D helical cooling coils in a tank in AutoCAD and imported it into Gambit. I had to create an imaginary coil around the real coil to "lure" the boundary layer outward into the tank instead of inward into the tube. I am having two problems:

(1) It appears that the mesh in the annulus region (ie. coopered volume from QUAD/PAVE mesh on one endcap face) does not match up with the mesh in the tank (TGRID). I believe that node points between two adjacent objects must match at the same node points. Can you recommend types of meshing that can rectify this?

(2) I defined the imaginary coil as a "porous-jump" in Gambit so that liquid can pass through it with any interference. However, when I import it into Fluent I get the error "cannot create porous-jump, changing to wall. Reason : only one adjacent cell thread." What is an adjacent cell thread?

Any help with one or both of these items would be greatly appreciated! Thank you.

-Eric R.