I stand corrected.
You seem to describe a large-ish centrifugal trash pump, mounted with the drive end up, mounted at the top of a cylindrical tank having a cylindrical baffle down its center.
Of course it can't pump anything until the tank is almost completely full.
I fail to see the need for a hollow motor, unless you actually require the ability to drop a cannonball into the water through the rotating impeller. Okay, maybe it's a magical instrument package.
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Every few years someone announces an axial flow pump with the vanes mounted to the inside of a rotating cylinder. I think the latest variation is a river turbine of considerable size. The devices usually disappear quietly, once the inventors hire an actual engineer and get the bad news about bearings and seals.
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Perhaps you are thinking of something like Dyson's magical bladeless fans. Such a thing is possible, sort of, with water. The actual pump is located off to the side somewhere. The part that they call a pump is actually an eductor. In a closed system, the hidden drive pump has to draw liquid from somewhere in the system. We might be able to suggest a location if we new what your apparatus was intended to do.
Mike Halloran
Pembroke Pines, FL, USA