FRANCIS TURBINES
DEFINITION
- It is type of water turbine.
- It is an inward flow reaction turbine that combines radial and axial flow concepts.
- They operate in a water head from 40 to 600 m.
- Primirly used in electrical power production.
- The speed of this turbine is 75 to 1000 rpm.
- It is always mounted with the shaft.
COMPONENTS
- Spiral casing
- Guide wanes
- Runner blades
- Draft tube
1. SPIRAL CASING
The spiral casing around the runner of the turbine knows as scroll case.It converts pressure energy of the fluid into momentum energy.The cross sectional area of casing decreases with uniformly along the circumstances.
2. GUIDE WANES
The primary function of this guide wanes is to convert pressure energy into momentum energy.It also serve to direct the flow at design to the runner blades.
3. RUNNER BLADES
Runner blades are the hearts of any turbines as these are centre where fluids are stricks . In this parts one has careful about the blades angles of inlet or outlet as these are the major affecting of power production.
4. DRAFT TUBE
The draft tube is a conduict which connects the runner exist to the tail race where the water is being discharge from turbines.The primary duty of draft tube is used to reduce the velocity of discharge water to minimise the loose of kinetic energy at the outlet.
APPLICATION
Frances turbine may be design for wide range of head and flow.Because of his high efficiency it become the most widely used turbines in the world.Francis type units cover a head of 40 to 600m
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