1. Guide vanes in Francis turbines

3. El Cajon, HONDURAS

4. Revelstoke, CANADA

5. P = 169 MW H = 72 m Q = 265 m 3 /S D 0 = 6,68 m D 1e = 5,71m D 1i = 2,35 m B 0 = 1,4 m n = 112,5 rpm 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 torqueLD Torque ArmLD

12. Guide vanes in closed position

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

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

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

16. c m1 Powerplantnsns 00 nsns 00 Skjærka6612Dynjafoss20827,5 Nedre Vinstra6912Oltesvik26438,5 Hol I7213Iverland26931,5 Mesna7813Fiskumfoss30840,5 Røssåga10418Fiskumfoss30836,5 Grønsdal11323Gravfoss34637 Nore II19834Solbergfoss36538

17. Powerplantnsns 00 1Skjærka6612 2Nedre Vinstra 6912 3Hol I7213 4Mesna7813 5Røssåga10418 6Grønsdal11323 7Nore II19834 8Dynjafoss20827,5 9Oltesvik26438,5 10Iverland26931,5 11Fiskumfoss30840,5 12Fiskumfoss30836,5 13Gravfoss34637 14Solbergfoss36538 The guide vane maximum angle  0 at full load NB: This is for Norwegian designed GE-turbines Specific speed, n s Guide vane angle

18. The servo’s work

19. 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 d f f (  )= empirical value  = friction factor H= Head

22. Stroke Friction Closing Opening Hydraulic forces Fully open Opening 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 k Bottom cover Guide vane shaft Head cover

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

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 D inlet Guide Vane r inlet Stay Vane B

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 D0D0 r1r1 B0B0

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  0 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 D1D1 D2D2

40. Statement of Problem Givens Net head …………..…. 201.5m Flow rate …………... 2.35m 3 /s Turbine speed …. 1000rpm Work out Design of Runner, Guide vanes, Stay vanes, Spiral casing andDraft tube CompareDesign output with Jhimruk turbines 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. Design Considerations

41. Design of Guide Vanes. D1D1 D2D2 Diameter of guide vane axis D 0 = D 1 (0.29 Ω+1.07) Chosen: Nos. of guide vanes z =20

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) = C m(gvo) /C u(gvo) α (gvo) = 12.21 0 Value of α gvo in full guide vane open position is selected 18 0

43. Design of Guide Vanes. Velocities at outlet, axis and inlet of guide vanes (depending on varing values of α and t) Outleta gvo =12.21 0 t gvo =5mm C m(gvo) = 8.582 m/sec C u(gvo) = 39.65 m/sec C gvo = 40.56 m/sec Axisa gvc =28.04 0 t gvc =30mm C m(gvc) = 9.521m/sec C u(gvc) = 17.87 m/sec C gvc = 20.25 m/sec Inleta gci =34 0 t gvi =15mm C m(gvi) = 7.864 m/sec C u(gvi) = 11.65 m/sec C gvi = 14.06 m/sec L = 204

44. Design of Guide Vanes.

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

46. Water from spiral casing Water particle