2.B] With a neat sketch explain the working principle of a Pelton Turbine
Answer:
Pelton wheel:
The Pelton wheel is the most commonly used type of impulse turbine. It works under a high head and requires small quantity of water. Figure shows a schematic sketch of a Pelton Wheel. The water from a high head source is supplied to the nozzle provided with a needle, which controls the quantity of water flowing out of the nozzle. The pressure energy of water is converted into velocity energy as it flows through the nozzle. The jet of water issuing out of the nozzle at high velocity impinges on the curved blades known as pelton cups, at the center as shown in the adjoining figure. The impulsive force of the jet striking on the Pelton cups sets up the pelton wheel to rotate in the direction the impinging jet. Thus the pressure energy of the water is converted into mechanical energy. The pressure inside the casing of the turbine will be at atmospheric pressure.