Difference Between Impulse & Reactive Steam Turbines

Steam turbines can be impulsive or reactive.

As their name suggests, steam turbines generate power through steam. They divide into two camps: impulsive and reactive, which work in different ways but still use the energy of the steam to produce electricity.

Impulse Turbine

Impulse turbines are the simpler variety --- they operate based purely on the impulse of the steam's movement. This is an easy concept to imagine; just blow on a piece of paper and you are acting on it with impulsive force. This same principle applies to impulse turbines.

Reactive Turbines

Reactive turbines take advantage of more properties of steam than just its movement. They do this through nozzles placed between the blades. The steam starts at the small end of the nozzle and goes to the large end; this means it goes from an area of high pressure to an area of low pressure, which makes it increase its speed. This force is transferred to the blades.

Similarities

All reactive turbines are also impulse turbines, but not all impulse turbines are reactive turbines. This is because it is the turbine blades that make them impulsive; reactive turbines add nozzles to the blades but they do not replace them.

References

• David Darling: Impulse Turbine
• TPub: Reaction Turbine