Location of Draft Tube in a Hydropower Station

The draft tube is an important component of a hydropower station that is used to convert the kinetic energy of water into useful mechanical energy. It is an airtight pipe that is located between the runner exhaust and the tailrace. The correct option is B.

Penstock and Runner

The penstock is a large steel pipe that carries water from the reservoir to the turbine. The water is then directed to the runner, which is a set of blades attached to a shaft. As the water flows through the runner, it causes the shaft to rotate, which in turn drives the generator to produce electricity.

Function of Draft Tube

After the water passes through the runner, it loses its kinetic energy and becomes low-pressure water. This low-pressure water needs to be discharged into the tailrace without causing any air cavitation. The draft tube is designed to create a low-pressure area at the outlet of the runner, which helps to reduce the pressure of the water and prevents air cavitation.

Air Cavitation

Air cavitation is the formation of air bubbles in the water due to low pressure, which can cause damage to the turbine and reduce its efficiency. The draft tube helps to prevent air cavitation by creating a smooth flow of water from the runner to the tailrace.

Surge Tank

The surge tank is another important component of a hydropower station that is located near the inlet of the penstock. It is used to regulate the flow of water to the turbine and prevent water hammer, which is a sudden increase in pressure that can damage the penstock and the turbine.

Conclusion

In conclusion, the draft tube is an airtight pipe that is located between the runner exhaust and the tailrace in a hydropower station. Its function is to prevent air cavitation and create a smooth flow of water from the runner to the tailrace. It is an important component that helps to improve the efficiency and reliability of the hydropower station.

B