Turbine - Definition and Types of Turbines

Definition

It is a device which converts mechanical energy into electrical energy or hydraulic energy into electrical energy. Turbines can also be termed as machines extracting energy from fluids.

Types of Turbines

1. Hydraulic turbines
2. Steam turbines

Hydraulic turbines

Water driven tubes are used primarily for the development of hydro-electric energy. There can be two basic types of hydraulic turbines.

1. Impulse or velocity turbines
2. Reaction or pressure turbines

Impulse or velocity turbines

In impulse turbines a free jet of water strikes the revolving element (runner/wheel) of a machine, which is exposed to atmospheric pressure. The total drop in pressure of water takes place in one or more stationary nozzles and there is no change in pressure of water as it flows through the rotating wheel.

Reaction or pressure turbines

A reaction turbine turbine is one in which the drop in pressure takes place in the rotating wheel. In reaction turbine the water enters the wheels under pressure and flows over the vanes or blades. In passing over the vanes, the pressure head is converted into velocity head and is finally reduced to atmospheric pressure before leaving the wheel.