Francis turbine

hi, I am sujon I just completed graduate at International University of Business Agriculture and Technology in Bangladesh Department of Mechanical Engineering

1. To Our Presentation Group Members: K M Nazmus Sakib 15207013 Md. Shakir Alom 15207014 Ariful Islam 15207016 Md sujon Babu 15207019 Md Rashidul Islam 15207021 Topic: Francis Turbine Group Number-05

2. Contents What is Turbine Basic Types of Turbine What is Francis Turbine Introduction of Francis Turbine Types of Francis Turbine Main Parts of Francis Turbine Working of Francis Turbine Efficiencies of Francis Turbine Advantages Disadvantages Recent Advancements Application of Francis Turbine How can we make it Economical Conclusion

3. What is Turbine

4. Basic Types of Turbine Steam Turbine Water Turbine Wind Turbine Gas Turbine

5. 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

6. Francis Turbine

7. Francis Turbine is an Inward Flow Reaction Turbine having Radial Discharge at Outlet. (i.e. = ). Modern Francis Turbine is a mixed flow type turbine (i.e. Water enters the runner of the turbine in the radial direction and leaves the runner in the axial direction). What is Francis Turbine

8. Introduction Francis turbines are the most common water turbine in use today. They operate in a water head from 10 to 650 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

9. Md. Shakir Alom

10. Sir James B. France 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’.

11. Types of Francis Turbine There are basic two types of Francis turbines according to the flow of water. Radial flow Francis Turbines: In this type of Francis turbine, water enters radially . This means the flow at entry is tangential to the runner. The water enters through guide vanes and then directed to runner blade. This type of design normally has less efficiency as compared to mixed or axial flow type. Normally they are designed for small - medium scale hydropower plants

12. Cont…. Mixed Flow Francis Turbines: In this type of turbine, the flow is directed in an angle between radial and axial. As per requirement a mixed flow Francis can be designed as reversible machine which can be used as pump. Turbines designed for radial flow normally has lesser flow rate than turbines that are designed for axial flow. Hence, the turbine speed increases and the increment in the shaft output power is achieved .

13. Penstock- I t is a large size conduit which conveys water from upstream to the dam/reservoir to the turbine runner spiral casing- I t constitutes a closed passage whose cross section area gradually decrease along flow direction area is maximum at inlet and nearly zero at exit . guide vanes- T hese vanes direct the water on the runner at an angle appropriate to the design, controlled by hand wheel or governor Main Parts of Francis Turbine

14. Main Parts Governing mechanism- I t changes the position of guide vanes to affect a variation in water flow rate, when the load condition on the turbine changes Runner and runner blades- T he driving force on the runner is both due to impulse and reaction effect(usually runner blades 16-24 ). Draft tube- I t is generally an expending tube which discharges the water, passing through the runner to the tail race.

15. Md. Ariful Islam

16. In the Francis turbines the water must be enter into inlet nozzle and the velocity must be decreases . Then the water moves in the forward direction in the turbine but continuous decrease in the spiral casing area must be happened. With the constant speed the water strikes the turbine blades .

17. So the motion takes place from the high pressure to the low pressure . Inside the blade it looks like a bucket it using the impulsive force for rotation of water . On the runner the blades are mounted. The blades are designed like a thin air foil. Cont ……

18. Cont …… If the flow rate of water changes then by using the governing mechanism we can set the angle of attack of the water on the blade. At that case the turbine works properly . Initially the water passes from the blades and next later enters into the draft tube, where we can notice the continuous increment in the area and velocity of the water must be decreases. So due to the design the water flow occurs at low pressure at one point and other side it creates a low pressure.

19. E fficienc ies of Francis 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. Power developed by the runner Power available at the inlet η h = Mechanical Efficiency – It is ratio of power available at the shaft to power developed at the runner. Power at the shaft of the turbine η m = Power developed by the runner

20. Volumetric Efficiency - It is ratio of volume of the water actually striking the runner to the volume of water supplied to the turbine. V olumetric e f ficiency ( η ) = volume of water striking the bucket volume of water supplied to the 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 ) = Power available to the shaft Power suppied at the inlet Cont ……

21. Md. S ujon Babu

22. Advantages 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. Very good efficiency(80-94%).

23. Disadvantages Its cost is very high. Its operation is simple but the design is very complex. Large number of moving parts are present. Its maintenance and repair is difficult task and expensive too . It is applicable to medium head levels only. Cavitation is also a big problem.

24. 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.

25. Problem: A Francis’ 135 kW turbine, having an overall efficiency of 75%, is required to produce under a head of 9 meter and at 120 r.p.m . The velocity of periphery of the wheel and velocity of flow at inlet is 3.47√H and 1.1√H respectively. If the hydraulic losses in the turbine are 20% of the available energy, find: Guide blade angle at inlet, Wheel vane angle at inlet, and Diameter of the wheel.

26. Md. Rashidul Islam

27. At first, F.turbine was used in industries to drive the machines via belts. Used to pump the water up when there is not much electricity needed. It is used in dams and water reservoirs to generate hydroelectric power. Application

28. Another big application of Francis turbine is Itaipu Dam in Brazil. Located on the Parana River between Brazil and Paraguay. One of the Seven Wonders of the Modern World. Second largest hydroelectric power plant. 87.8 TWh generated in 2014. 118m of hydraulic head. 20 Francis turbines. 700 MW each

29. We use New types of designs to reduce the cost and complexity of mechanism. Modified turbine include lnline Link less Francis turbine, Cross flow turbine These new turbine require less space, simplified designed , less moving parts, etc .

30. Conclusions Francis turbines are one of the most widely used turbines of our time . Extremely high efficiency at specific flows. Come in many sizes and are very versatile. Large range of power outputs. Wanted when dealing with relatively medium head and high flows.

31. Any Question