Classification of hydraulic turbine

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 position of turbine shaft

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 flows either
towards the axis of rotation or away from it.
Radial flow turbine is of two types:
I. Inward flow turbine : If the flow of water is towards the axis
of rotation, its called inward flow turbine.
II. 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 15-60 m
Ex- kaplan turbine

15. Based on specific speed
Specific speed Types of turbine
10-35 Pelton wheel with one nozzle
35-60 Pelton wheel with two or more
nozzle, Multi jet pelton wheel
60-300 Francis turbine
300-1000 Kaplan turbine

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

17.  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.

19. Pelton Wheel (Pelton turbine)
 THIS TURBINE IS NAMED AFTER
LESTER A. PELTON (1829 – 1908)
AN AMERICAN
ENGINEER WHO DEVELOPED IT
IN THE YEAR 1880.
 PELTON WHEEL IS A HIGH HEAD
TURBINE. IT IS USED WITH HEADS
OF MORE THAN 500 METRES.
NOTE : A HEAD IS THE DISTANCE
THE WATER FALLS BEFORE IT
STRIKES THE TURBINE BLADES.
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20. Pelton Wheel (Pelton turbine)…
 The flow of water is tangential to
the runner. So it is a tangential
flow impulse turbine.
 A Pelton’s runner consists of a
single wheel mounted on a
horizontal shaft.
 Water falls towards the turbine
through a pipe called penstock
and flows through a nozzle.
 The high speed jet of water hits
the buckets (vanes) on the wheel
and causes the wheel to rotate.
 A spear rod which has a spear
shaped end can be moved by a
hand wheel.
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This movement controls the flow of
water leaving the nozzle, before it
strikes the bucket(vane)

21. Pelton Wheel (Pelton turbine)…
THE BUCKET OR VANE IS SO SHAPED THAT WHEN THE WATER
STRIKES, IT GETS SPLIT INTO
TWO AND GIVES IT AN IMPULSE FORCE IN THE CENTRE OF THE
BUCKET. THIS BUCKET IS
ALSO KNOWN AS SPLITTER.
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22. 22
Pelton Wheel (Pelton turbine)…

23. 23
Pelton Wheel (Pelton turbine)…

24. 24
Pelton Wheel (Pelton turbine)…

25. 25
Pelton Wheel (Pelton turbine)…

26. Francis turbine
 IT IS NAMED AFTER JAMES B. FRANCIS (1815 – 1892) AN ENGLISH
BORN INVENTOR
WHO DEVELOPED THE TURBINE IN THE YEAR 1849.
 IT IS USED WHEN THE HEAD IS BETWEEN 80 TO 300 METRES. I.E.
IT IS A MEDIUM HEAD
TURBINE.
 IT IS A MIXED FLOW REACTION TURBINE.
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27. Francis turbine
 A Francis turbine rotates in a closed casing.
 Its wheel has many curved blades called
runner vanes as many as 24.
 Its shaft is vertical. The wheel of a Francis
turbine operates under water.
 The guide vanes and stay vanes control the
amount of water flowing into the runner
vanes.
 The runner is rotated mainly due to the
weight or pressure of the flowing water.
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28. Kaplan turbine
 Kaplan turbine is a type of propeller turbine which was developed during
1900’s by the Austrian engineer Victor Kaplan (1876 – 1934)
 Kaplan turbine is a low head turbine and used for heads of less than 80
metres.
 The runner of a kaplan turbine resembles with propeller of a ship. That is
why, a Kaplan turbine is also called as propeller turbine.
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29. Kaplan turbine
 The turbine wheel, which is
completely under water, is turned by
the pressure of water against its
blades.
 Guide vanes regulate the amount of
water reaching the wheel.
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30. Kaplan turbine
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31. Kaplan turbine
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32. Hydraulic turbines…
DIFFERENCE BETWEEN KAPLAN TURBINE AND
FRANCIS TURBINE:
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Sl.No. Kaplan turbine Francis turbine
1 Water enters the runner vanes
axially and leaves axially, hence it
is called axial flow turbine.
Water enters the runner vanes
radially and leaves axially, hence it
is called a mixed flow turbine.
2 The number of blades in the
runner is generally between 3 and
8.
The number of blades in the runner
is generally between 16 and 24.

33. Hydraulic turbines…
DIFFERENCE BETWEEN IMPULSE AND
REACTION HYDRAULIC TURBINES:
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Sl.No. Impulse turbine
e.g. Pelton turbine
Reaction turbine
e.g. Kaplan & Francis turbines
1 In an impulse turbine all the
available energy of water is
converted into kinetic energy as it
passes through a nozzle.
In a reaction turbine, at the entrance
to the runner, only a part of the
available energy of water is
converted into kinetic energy and a
greater part remains in the form of
pressure energy.
2 The water flowing through the
nozzle impinges on the buckets
which are fixed on the outer
periphery of the wheel.
The water is guided by the guide
blades to flow over the runner
vanes.