1. HYDRAULIC TURBINES AND ITS CLASSIFICATION

2. Definition
Hydraulic Turbine is a prime mover that uses the energy of flowing water and converts it into the mechanical energy in the form of rotation of runner wheel.
Also termed as ‘water turbines’.

3. Flow sheet of hydroelectric power plant

4. Classification Based on hydraulic action of water
Based on direction of flow
Based on head of water and quantity of flow
Based on specific speed
Based on disposition of turbine shaft
Based on name of originator (commonly used turbines)

5. Based on hydraulic action of water
Impulse turbine : One in which all the energy of water is converted to kinetic energy before the water strikes the vanes of the runner wheel. This is done by passing the flow through nozzle or some guidelines. The runner is rotated by the force of water and water passes over the wheel at atmospheric pressure.
Ex- Pelton Wheel

6. Impulse Turbine

7. Reaction Turbine : Here, water entering the runner wheel of the turbine has both kinetic energy and pressure energy that is total head of water striking the runner wheel ,consist partly of pressure head.
E.g- Francis turbine, Propeller turbine, Kaplan turbine

8. Reaction Turbine (Kaplan Turbine)

9. Based on direction of flow
Radial flow turbine : A radial flow turbine is a turbine in which the water as it move along the vane flow towards the axis of rotation or away from it.
Radial flow turbine is of two types:
Inward flow turbine : If the flow of water is towards the axis of rotation, its called inward flow turbine.
Outward flow turbine : If the flow of water is away from the axis of rotation , its called outward flow turbine.

10. Radial Flow Turbine

11. Axial flow turbine : Its the turbine in which water enters the runner wheel parallel to the direction of axis of rotation of runner.
Ex- Kaplan turbine, Propeller turbine
Tangential flow turbine : Its the turbine in which water strikes the runner wheel tangentially to the path of rotation.
Ex- Pelton turbine

12. Axial Flow Turbine

13. Mixed flow turbine : It’s the turbine in which the direction of flow is partly radial and partly axial. Water enters the blade radially and comes out axially parallel to the turbine shaft.

14. Based on head of water and quantity of flow
High head turbine : when head is above 250 m
Ex- Pelton wheel
Medium head turbine : when head is between 60m – 250m
Ex- Francis turbine
Low head turbine : When head is between m
Ex- kaplan turbine
Very low head turbine: When is head is less than 15m
Ex- Propeller turbine

15. Based on specific speed
Specific speed Types of turbine Pelton wheel with one nozzle Pelton wheel with two or more nozzle, Multi jet pelton wheel Francis turbine Kaplan turbine

16. Based on disposition of turbine shaft
Turbine shaft may be either vertical or horizontal. Pelton turbine usually have horizontal shafts whereas the rest have vertical shafts.

17. Based on name of originator
Pelton wheel : Tangential flow impulse turbine used for high head of water.
Francis turbine : Inward flow reaction turbine used for medium head of water.
Kaplan turbine : Axial flow adjustable blades reaction turbine used for low head of water.
Propeller turbine : Fixed blades axial flow reaction turbine used for very low head of water.

18. Francis Turbine Propeller Turbine Kaplan Turbine