Go ahead and add a lid (model a volume) at the centerline of each duct. Do not disable the lid. On the inlet face apply an 'Outlet' condition, such as 'Outlet Velocity'. On the outlet face, apply an 'Inlet' condition, such as 'Inlet Velocity'.
But if i model a volume contained in the fan, just to apply bc's,
I modified your part using SW 2011, see attached. Load Flow Sim and just run it, you'll see how it works.
perfil naca pplane2.zip 717.1 KB
Thank you! And really thank you for spending your time with my question. So with such volume i can simulate an actuator disk, perfect. I already tried to put lids (not with an extruded solid, but using lid command) on each duct inlet face, but i got an error like "the face doesn't lie on the solid-fluid boundary"...May be it was because i did it wrong and there was any sort of interference between lids and duct walls.
Anyway, again, lot of thanks, it seems i can follows in this way (waiting for contra-rotatings ).