Lesson 2/Learning Event 2
Compression increases as the air is whirled from the center outward, and more air rushes in to fill the void
at the center. The compressed air occupies a progressively smaller volume as it travels from the hub, and the
velocity of the air decreases in passing from the hub to the perimeter, Decrease of velocity with rise in
pressure is called diffuser compression.
There are three steps in compression in a centrifugal supercharger. These are caused by centrifugal action,
diverging contours at outer perimeter, and action of the diffuser plate.