Thanks ! (I’m not sure ceiling fan analogy quite works since the moving air is not contained…)
Why isn't it contained? Its contained in a room. The impeller is contained in a housing the difference is the speed. You put a large fan in a small room with curved walls and ducts on top and bottom it's very similar. Water being un-compressable would cause some issues in a centrifugal pump with high speed and a tightly spaced housing. But a common tiny circulator is not made the same as an industrial high horse power high speed pump.
