- Impulse turbine
- Reaction turbine
Impulse Turbine
An impulse turbine generally uses the velocity of moving water to run the turbine and discharge at atmospheric pressure. The potential energy of water is converted into kinetic energy through a nozzle. The velocity water jet strikes the blades and drive the the wheel of water turbine. The high speed water jet striking the turbine blades causes the turbine to rotate. The change in momentum (impulse) exerts a push on turbine blades due to which the the turbine rotates.
The water flowing over the turbine blades remains at constant atmospheric pressure and turbine operates with the change in kinetic energy of the moving water. An impulse turbine is suitable for high head and low flow applications. There are mainly three types of impulse turbine which are listed below.
- Pelton Turbine
- Turge Turbine
- Cross-flow Turbine
Reaction Turbine
Reaction turbine uses the combine forces of pressure and moving water to generate power. It operates by placing the turbine directly in a water stream and allowing water to flow over the blades rather than striking each blades individually. The water flow creates pressure between the front and rear blades creating a reverse reaction force on the turbine generating sufficient rotating torque to rotate the turbine.
Reaction turbine has an expansion section called draft tube at the exit. The draft tube is to collect the kinetic energy of moving water at the exit and increase pressure due to which efficiency of the turbine increases. Reaction turbine is generally used for low head and high flow applications. There are mainly two types of reaction turbine which are listed below.
- Propeller Turbine ( including kaplan turbine )
- Francis Turbine