1. Guide vanes in Francis turbines

3. El Cajon, HONDURAS

4. Revelstoke, CANADA

5. La Grande 3, Canada P = 169 MW H = 72 m Q = 265 m3/S D0 = 6,68 m
D1e = 5,71m
D1i = 2,35 m
B0 = 1,4 m
n = 112,5 rpm

6. La Grande 3, Canada

7. La Grande 3, Canada

8. Guide vane cascade, Francis

9. Guide Vane End Seals High efficiency Less erosion
Less leakage in closed pos.

10. Guide vanes Main function: Adjust the turbine load
The guide vanes consist of number of blades that can be adjusted in order to increase or reduce the flow rate through the turbine. The vanes are arranged between two parallel covers normal to the turbine shaft.

11. Pressure distribution and torqueL D
Torque
Arm L D

12. Guide vanes in closed position

13. Guide vanes in open position
Pressure distribution can be found using Bernoulli’s equation:
Pressure distribution along the contour of the guide vane:
Trailing edge
Trailing edge
Contour of the guide vane

14. Pressure distribution along the contour of the guide vane:
Small flow rate
Large flow rate
Stagnation-
Point at Leading Edge
Guide vane contour

15. Variation of the torque when the guide vane opening changes:2 3 1 4
Sin a0

16. cm1 Powerplant ns a0 Skjærka 66 12 Dynjafoss 208 27,5 Nedre Vinstra 69
Oltesvik
264
38,5
Hol I 72 13
Iverland
269
31,5
Mesna 78
Fiskumfoss
308
40,5
Røssåga
104 18
36,5
Grønsdal
113 23
Gravfoss
346 37
Nore II
198 34
Solbergfoss
365 38

17. The guide vane maximum angle a0 at full load
Powerplant ns a0 1
Skjærka 66 12 2
Nedre Vinstra 69 3
Hol I 72 13 4
Mesna 78 5
Røssåga
104 18 6
Grønsdal
113 23 7
Nore II
198 34 8
Dynjafoss
208
27,5 9
Oltesvik
264
38,5 10
Iverland
269
31,5 11
Fiskumfoss
308
40,5
36,5
Gravfoss
346 37 14
Solbergfoss
365 38
NB: This is for Norwegian designed GE-turbines
Guide vane angle
Specific speed, ns

18. The servo’s work

19. Take care of the torque from all guide vanes for all guide vane angles
The servo has to:
Take care of the torque from all guide vanes for all guide vane angles
The torque consist of:
Hydraulic torque
Friction torque

20. Hydraulic torque
The hydraulic torque can be found from a CFD-analysis

21. Friction torque ff (W,a)= empirical value m = friction factor H = Head

22. Stroke
Friction
Closing
Opening
Hydraulic forces
Fully open
High head Francis turbine
Measurements of the servo’s work
Force in 1000 kg

23. Horse shoe vortex damage

25. Cavitation damage

26. Sand erosion in the guide vanes
Jhimruk Hydro Power Plant

27. Head cover
Head cover
Head cover
Guide vane shaft k
Bottom cover

29. The deflection of the head cover
H = 435, P = 25 MW 1 2

30. Reduction of clearance

31. Efficiency of repaired turbine
[MW]
H = 430 m

32. Design of the Guide Vane Inlet Angle
The inlet angle can be calculated by assuming a free vortex from the flow coming from the spiral casing B
Dinlet Guide Vane
rinlet Stay Vane

33. Design of the Guide Vane Outlet Angle
The outlet angle can be calculated by assuming a free vortex from the flow in the gap between the runner and the guide vanes B0 r1 D0

34. Design of the Guide Vanes How to choose the number of vanes
The number of guide vanes has to be different from the number of runner vanes.

35. Design of the Guide Vanes How to choose the number of vanes
The number of guide vanes has to be different from the number of runner vanes.

36. Design of the Guide Vanes How to choose the guide vane maximum angle a0 at full load

37. Design of the Guide Vanes Overlapping of the guide vanes

38. Design of the Guide Vanes Number of guide vanes

39. Design of the Guide Vanes Diameter of guide vane shaft

40. Design Considerations
Statement of Problem
Givens Net head…………..….201.5m Flow rate………… m3/s Turbine speed….1000rpm Work out Design of Runner, Guide vanes, Stay vanes, Spiral casing andDraft tube Compare Design output with Jhimruk turbines
Design Considerations
Calculations - based on hydraulic principles only, Thickness of runner blades - neglected, Designs of components - done for the best efficiency point, Other several assumptions - mentioned locally in calculations.

41. Design of Guide Vanes Chosen: Nos. of guide vanes z =20
Diameter of guide vane axis D0 = D1 (0.29 Ω+1.07) .

42. Design of Guide Vanes Tangential and meridional velocities
Assuming gap between runner and guide vanes 5% of the runner inlet diameter. .
tan α(gvo) = Cm(gvo)/Cu(gvo)
α(gvo) =
Value of αgvo in full guide vane open position is selected 180

43. Design of Guide Vanes
L = 204
Velocities at outlet, axis and inlet of guide vanes (depending on varing values of α and t)
Outlet agvo= tgvo=5mm
Cm(gvo) = m/sec Cu(gvo) = m/sec Cgvo = m/sec .
Axis agvc= tgvc=30mm
Cm(gvc) = 9.521m/sec Cu(gvc) = m/sec Cgvc = m/sec
Inlet agci= tgvi=15mm
Cm(gvi) = m/sec Cu(gvi) = m/sec Cgvi = m/sec

44. Design of Guide Vanes .

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

46. Water particle
Water from spiral casing