Class Presentation

3. CIVIL DEPARTMENT
GROUP : G
( ROLL NO 60 TO ROLL NO 70 )
BATCH :
( 2013 -2017)

4. Group Members:
Tahzeeb Hussain ( Group leader )
Suliman khan
Asad Ali Ghillani
Shoukat mengal
Huzaifa
Munir
Kazim khan
Imran ull llah
Tahir khan

5. FRANCIS TURBINe

6. Introduction
Turbine:
 A turbine is a rotary mechanical device that
extracts energy from a fluid flow and converts it into
useful work.
 Turbines are used in boat propulsion systems,
hydroelectric power generators, and jet aircraft engines.
 Used for hydro electric power, i.e. cheapest source of power
generation.
 hydraulic energy mechanical energy electrical
energy
 power generating device

7. Basic Types of Turbine
 Steam Turbine
 Water Turbine
 Wind Turbine

8. Types Based Energy Used
Impulse turbine :
Only kinetic energy of water is
used to drive turbine.
Eg.Pelton Turbine
Reaction turbine :
Kinetic energy as well as Pressure
energy of water is used to drive turbine.
Eg.Francis Turbine

9. Introduction:
Francis turbines are the most common
water turbine in use today.
They operate in a water head from 10 to 700
meters (33 to 2,133 feet).
They are primarily used for electrical power
production.
The turbine powered generator power
output generally ranges from 10 to
750 megawatts

11. History
This turbine was invented by Sir James
B. France in Lowell, Massachusetts,
U.S.A.
Studying the Boyden turbine ,Francis
was able to redesign it to increase
efficiency.
Boyden Turbine could achieve a 65
percent efficiency.
So, James France redesigned this
turbine and new turbine with 88%
efficiency was invented.
This was known as ‘Francis turbine’.

12. 1848 1849 1859 1868
1873 1876 1902 1920

13. The Boyden Turbine

14. Studying the Boyden turbine Francis was able
to redesign it to increase efficiency.
Constructing turbines as “sideways water
wheels,” Francis was able to achieve an
astounding 88 percent efficiency rate.
After further experimenting, Francis developed
the mixed flow reaction turbine which later
became an American standard.
Twenty-two of the “Francis turbines” reside in
Hoover Dam to this day.
His work on these turbines was later published
as The Lowell Hydraulic Experiments in 1855.

15. The Francis Turbine

16. Components of Francis
turbine:
 Penstock
 Spiral casing
 Guide vanes/ Stay vanes
 Runner and Runner blades
 Draft tube
SPIRAL CASING

17. • Parts of A Francis
Turbine

18. Working
Penstock:
It is a large size conduit which conveys
water from the upstream to the dam/reservoir
to the turbine runner.

19. • Runner is fitted, inside a spiral casing.
• Flow is entered via an inlet nozzle. Flow rate of water will get reduced along length of
casing, since water is drawn into the runner.
• But decreasing area of spiral casing will make sure that, flow is entered to runner
region almost at uniform velocity.

20. Guide Vanes:
• Stay vanes and guide vanes are fitted at
entrance of runner.
• These vanes direct the water on to the runner
at an angle appropriate to the design, the
motion of them is given by means of hand
wheel or by a governor.
• The primary function of the guide or stay
vanes is to convert the pressure energy of
the fluid into the momentum
energy/Kinetic energy.
• It also serves to direct the flow at design
angles to the runner blades.
• Flow which is coming from the casing, meets
stay vanes, they are fixed.
• .

21. • Stay vanes steers the flow towards the runner section.
• Thus it reduces swirl of inlet flow
Stay vanes
Guide vane
Runner

22. R a d i a l v i e w
runner guide vanes and stay vanes
R a d i a l v i e w
runner guide vanes and stay vanes
R a d i a l v i e w
runner guide vanes and stay vanes
R a d i a l v i e w
runner guide vanes and stay vanes
R a d i a l v i e w
runner guide vanes and stay vanes
R a d i a l v i e w
runner guide vanes and stay vanes
R a d i a l v i e w
runner guide vanes and stay vanes
R a d i a l v i e w
runner guide vanes and stay vanes
R a d i a l v i e w
runner guide vanes and stay vanes
R a d i a l v i e w
runner guide vanes and stay vanes
R a d i a l v i e w
runner guide vanes and stay vanesR a d i a l v i e w
runner guide vanes and stay vanes
Water from
spiral casing
Water particle
Motion of water particle:

23. Guide vanesGuide vanesGuide vanesGuide vanesGuide vanesGuide vanes
Runner inlet
(Φ 0.870m)
Guide vane outlet for designα)
(Φ 0.913m)
Closed
Position
Max. Opening
Position

24. Operation of Guide Vanes
Guide vane at Design
Position = 12.21°
Guide vane at closed position
Guide vane at Max. open
Position = 18°
.

25. Motion of water relative to Blade:
Diagrams:

26. Runner and Runner blades:
 The driving force on the runner is both due to impulse and reaction effect. The
number of runner blades usually varies between 16 to 24.
• Runner blades are the heart of any turbine. These are the centers
where the fluid strikes and the tangential force of the impact causes
the shaft of the turbine to rotate, producing torque.
• . It is fitted with a collection of complex shaped blades as shown in
Fig.
• In runner water enters radially, and leaves axially. During the course
of flow, water glides over runner blades as shown in figure below.

27. • Blades of Francis turbine are specially shaped as shown in figure. It is
clear from the figure that shape of blade cross-section is of thin
airfoils.
• So, when water flows over it, a low pressure will be induced on one
side, and high pressure on the other side.
• This will result in a lift force.

28. • It is having a bucket kind of shape towards the outlet.
• When water will hit, then it produce an impulse force before
leaving the runner.
• Both impulse force and lift force will make the runner rotate.
• Therefore, as water flows over runner blades both its kinetic and pressure energy will
come down.
• Since flow is entering radially and leaves axially, they are also called ‘mixed flow
turbine’.
• Runner is connected to generator, via a shaft, for electricity production

29. Runner with Generator:

30. Draft tube:
• The draft tube is gradually expanding conduit
which discharges water from the turbine,
passing through the runner to the tail race.
• Its primary function is to reduce the velocity
of discharged water to minimize the loss of kinetic
energy at the outlet.
• This permits the turbine to be set above the tail water without appreciable drop of
available head.
Draft tube

31. Governing Mechanism:
• When the load condition on the turbine changes then the position of guide vane also
changes to control water flow rate.
• It also makes sure that power production is synchronized with power demand.
• Guide vanes also control flow angle to inlet portion of runner blade.
• Thus guide vanes make sure that inlet flow angle is at optimum angle of attack for
maximum power extraction from fluid.

33. Francis Turbine Power Plant :
A Continuous Hydraulic System

34. The Francis Installation

35. Cavitation:
 Cavitation is an important problem in hydraulic machines that negatively affects
their performance and may cause damages.
 Cavitation is a phenomenon which manifests itself in the pitting of the metallic
surfaces of turbine parts because of the formation of cavities.
 The reaction turbines operate under low and medium head with high specific
speed and operate under variable pressure.
 Cavitation in hydraulic machines negatively affects their performance and may
causes severe damages.

36. Damages caused by cavitation if summarized are:
• Erosion of material from turbine parts.
• Distortion of blade angle.
• Loss of efficiency due to erosion/distortion
Main causes 0f damages:
1= erosive wear of the turbines due to high content of abrasive material
carried over by water.
2= Cavitation

38. (a) Draft tube swirl (b) Travelling edge cavitation
(c) Leading edge cavitation (d) Inter-blade vortex cavitation

39. Efficiency of Turbine
Hydraulic Efficiency - It is ratio of power developed by the
runner of a turbine to the power supplied by the water at the
inlet.
𝛈 𝐡 =
𝐏𝐨𝐰𝐞𝐫 𝐝𝐞𝐯𝐞𝐥𝐨𝐩𝐞𝐝 𝐛𝐲 𝐭𝐡𝐞 𝐫𝐮𝐧𝐧𝐞𝐫
𝐏𝐨𝐰𝐞𝐫 𝐚𝐯𝐚𝐢𝐥𝐚𝐛𝐥𝐞 𝐚𝐭 𝐭𝐡𝐞 𝐢𝐧𝐥𝐞𝐭
Mechanical Efficiency – It is ratio of power available at the
shaft to power developed at the runner.
𝛈 𝐦 =
𝐏𝐨𝐰𝐞𝐫 𝐚𝐭 𝐭𝐡𝐞 𝐬𝐡𝐚𝐟𝐭 𝐨𝐟 𝐭𝐡𝐞 𝐭𝐮𝐫𝐛𝐢𝐧𝐞
𝐏𝐨𝐰𝐞𝐫 𝐝𝐞𝐯𝐞𝐥𝐨𝐩𝐞𝐝 𝐛𝐲 𝐭𝐡𝐞 𝐫𝐮𝐧𝐧𝐞𝐫

40. 














g
V
h
g
V
h
Losseshydraulic
g
V
h
g
V
h
hydraulic
22
22
2
3
3
2
1
1
2
3
3
2
1
1

 Hydraulic efficiency of Francis turbine:
• Overall Efficiency - It is ratio of power available at the shaft
of the turbine to the power supplied by the water at the inlet of
the turbine.
• 𝐎𝐯𝐞𝐫𝐚𝐥𝐥 𝐞𝐟𝐟𝐢𝐜𝐢𝐞𝐧𝐜𝐲 𝜼 𝒐𝒗 =
𝐏𝐨𝐰𝐞𝐫 𝐚𝐯𝐚𝐢𝐥𝐚𝐛𝐥𝐞 𝐭𝐨 𝐭𝐡𝐞 𝒔𝒉𝒂𝒇𝒕
𝐏𝐨𝐰𝐞𝐫 𝐬𝐮𝐩𝐩𝐢𝐞𝐝 𝐚𝐭 𝐭𝐡𝐞 𝒊𝒏𝒍𝒆𝒕
𝐍𝐨𝐫𝐦𝐚𝐥 𝐨𝐯𝐞𝐫𝐚𝐥𝐥 𝐞𝐟𝐟𝐢𝐜𝐢𝐞𝐧𝐜𝐲 𝜼 𝒐𝒗 = 𝜼 𝒗 ∙ 𝜼 𝒎 ∙ 𝜼 𝒉

41. Relevant Equations:

43.  COMPARISON

44. It is a most widely used turbine in
world (about 70-80%).
Effective use of water pressure as
well as velocity.
It is American standard turbine.

47. Cost is High.
Due to its complex design and large
number of moving parts,
maintenance and repair is difficult
and costly.
It is applicable to flow of medium head
only.

48. Recent Advancements:
New types of designs are developed
to reduce cost and complexity of
mechanism.
Modified turbine include Inline
Linkless Francis Turbine, Cross-
flow Turbine,etc.
These new turbine require less space,
simplified designs, less moving parts,
etc.

49. Applications:

50. PRACTICAL USES:

52. • Guri Hydroelectric Power Plant in Orinoco,
Venezuela