2. Jets & Buckets for Pelton Wheels Means to Complete the Second Law of Power Retrieval……. P M V Subbarao Professor Mechanical Engineering Department

3. Geometrical Relations for Nozzle dOdO 2d O – 2.4d O 5d O – 9d O 0.8d O – 0.9d O 1.2d O – 1.4d O 1.1d O – 1.3d O

4. Numerical Computation of Total Pressure Variation

5. Jet carrying a discharge of Q to deliver a power P To generate a discharge of Q, we need a least jet diameter of Acceptable Performance of Nozzle

6. Diameter of the Jet at the outlet, d o It is important to find out the VC and outlet jet diameters/areas The Diameter of Jet before Reaching Bucket

7. A Set of Relations A jet of finite velocity needs to have a relation with peripheral velocity of wheel. A jet of finite area need to have a relation with dimensions of bucket. A bucket of finite dimensions and shape should have a relation with wheel.

8. Jet Vs Mean Diameter of Pelton Runner Mean diameter or Pitch circle diameter: D wheel Circumferential velocity of the wheel, U wheel D wheel

9. Jet Power & Conditions for Maximum Power Define, Blade Speed Ratio as

10. Implication of Maximum Power Condition

11. For maximum efficiency

12. Optimal values of Wheel diameter to jet diameter NsNs

13. Experimental values of Best values of Wheel diameter to jet diameter D wheel /d jet,VC 6.57.51020 N s (rpm)35322410  turbine 0.820.860.890.90 P in hp, H in meters and N in rpm Essential to have a minimum of 10 for acceptable turbine efficiency.

14. The highest ratio used in the world is 110 (Kt. Glauraus Power House in Switzerland). Specifications of this Pelton wheel are: Power 3000HP (2.24MW)Speed: 500 rpm D wheel = 5.36md jet,VC =48.77mm Head =1,650 m Extreme Engineering Conditions

15. The Second Relation : Jet Vs Bucket

16. External stroboscopic flow visualization

17. Runner with Advanced Buckets

18. Bucket Displacement Diagram

19. A notch made near the edge of the outer rim of each bucket is carefully sharpened to ensure a loss-free entry of the jet into the buckets, i.e., the path of the jet is not obstructed by the incoming buckets.

20. BUCKET GEOMETRIC DEFINITIONS

21. Geometric Details of Bucket The hydraulic efficiency depends more on the main bucket dimensions (length (A), width (B) and depth (C)). The shape of the outer part of its rim or on the lateral surface curvature also has marginal effect on hydraulic efficiency.