This presentation demonstrates the working and governing of Francis turbine

1. FRANCIS TURBINE
Working and Governing Mechanism.
Santosh Kurre Sharad Walia
Professor B. Tech (Mechanical)
UPES, Dehradun UPES, Dehradun

2. TURBINE
• A hydraulic turbine is a machine that uses the potential and
kinetic energy of water and converts it into usable mechanical
energy.
• This mechanical energy is used in running an electric generator
which is directly coupled to the shaft of the turbine, thus this
mechanical energy is converted into electrical energy

3. Types of turbine
(basedontheactionofwaterflowingthroughtheturbinerunners)
•IMPULSE
TURBINE
• Only kinetic energy
of water is used to
drive turbine.
• e.g. - Pelton Turbine
•REACTION
TURBINE
• Kinetic energy as
well as Pressure
energy of water is
used to drive turbine.
• e.g.- Francis Turbine

4. FRANCIS TUBINE
• Francis turbine is a mixed flow type of reaction turbine.
• Francis turbine is a mixed flow type as water enters the runner
radially at its outer periphery and leaves axially at its centre.
• In today’s use, Francis turbines are the most common
water turbine.
• They operate in a water head from 60 to 250 metres.

5. Sir James B. Francis
• The Francis turbine was
developed by James B.
Francis in Lowell,
Massachusetts, USA.
• Sir Francis was the first to
develop an inward radial
flow type of reaction turbine
in 1849.

6. Layout of a hydroelectric power plant

7. Francis turbine installation

8. A schematicpresentationof Francisturbine

9. ElementsofaFrancisturbine

10. Components
• Penstock: It is a large size conduit which conveys water
from the upstream of the dam to the turbine runner.
• Spiral Casing: It constitutes a closed passage whose cross-
sectional area gradually decreases along the flow direction.
It ensures that the velocity of water is constant along its
path.
• Stay Vanes: Stay vanes and guide vanes guides the water to
the runner blades. Stay vanes remain stationary at their
position and reduces the swirling of water due to radial flow,
as it enters the runner blades. Thus making turbine more
efficient.

11. Flow throughstay and guidevanes.

12. Cont…
• Guide Vanes: These vanes direct the water onto the runner
at an angle appropriate to the design.
• Guide vanes only swing around their own axes and this
helps to bring about a change in the flow area between two
consecutive runner blades.
• The configuration and arrangement of the guide vanes is
such that the energy of the water is not consumed by eddies
and other undesirable flow phenomenon causing energy
loss.
• Motion is given to the guide vanes either by means of a
hand wheel or automatically by a governor.

13. Cont…
• Runner and Runner Blades: The driving force on the
runner is both due to impulse and reaction effect.
• Design of the runner blades decides how well a turbine is
going to perform.
• Runner blades of mixed flow turbine can be divided into two
parts, the upper part of the blades use the reaction force of
water flowing through it and the lower half is in the shape of a
small bucket using the impulse action of water flowing through
it. These two forces together makes the runner to rotate.
• The runner is keyed to the shaft which may be of vertical or
horizontal disposition, the shafts are mostly vertical.

14. Flow of water through Runner

15. Cont…
• Draft tube: After passing through the runner, water is
discharged to the tail race through a gradually expanding tube,
called the draft tube.
• The free end of the draft tube is submerged deep into the tail
race.

16. Governing of Francis turbine

17. Governing of Francis turbine
• Speed of the turbine runner is required to be maintained
constant so that the electric generator coupled directly to the
turbine shaft runs at constant speed under varying load
conditions.
• This task is accomplished by governing mechanism.

18. AschematicrepresentationofGoverningmechanismof Francisturbine

19. Cont…

20. Cont…

21. Cont…