The centrifugal design uses the centrifugal force generated by a rotating disk, with blades mounted at right angles to the disk, to impart movement to the air or gas and increase its pressure.
The assembly of the hub, disk and blades is known as the fan wheel, and often includes other components with aerodynamic or structural functions. The centrifugal fan wheel is typically contained within a scroll-shaped fan housing.
The air or gas inside the spinning fan is thrown off the outside of the wheel, to an outlet at the housing’s largest diameter. This simultaneously draws more air or gas into the wheel through the central hole..