impeller.  Compared with standard axial fans, they can provide similar air movement from smaller fan components and overcome higher resistance in the air flow.
Centrifugal fans use the kinetic energy of the impeller to move the air flow, which in turn overcomes the resistance generated by pipes, baffles and other components. The centrifugal fan displaces the air radially and changes the air flow direction (usually 90 °). They are strong, quiet, reliable and can operate under various conditions.