Jet Propulsion/Axial turbine design/Stages

A rotor and stator combination is called a stage. The number of stages depends on the velocity of the rotor and the pressure drop required. Gas nozzles can impart high supersonic velocities to the fluid if the pressure is available. The proportion of this energy the rotor can extract depends on its velocity. Increasing the number of stages allows us to reduce the rotor velocity for a given power extracted from the fluid flow.