Innovative Design of Francis Turbine for Sediment Laden Water

1. International Conference on TIM, 2012, Nepal Innovative Design of Francis Turbine for Sediment Laden Water Krishna Prasad Shrestha1 BholaThapa1, Ole Gunnar Dahlhaug2 HariP. Neopane1 BirajSingh Thapa1 1Dept. Mechanical Engineering, Kathmandu University, P.O. Box 6250, Dhulikhel, Nepal 2 Dept. Energy&Process Engineering, Norwegian University of Science and Technology, NTNU, Trondheim, 7491, Norway Email: kp@ku.edu.np

2. International Conference on TIM, 2012, Nepal Outline • Introduction • Objectives • Methodology • Design of Francis runner • Core design process • Fluid Structure Interaction (FSI) • Limitations • Results and Discussion • Conclusions and Recommendation

3. International Conference on TIM, 2012, Nepal Introduction • Hydro turbine running in the Himalayas and Andes Mountain of the South America are facing the same challenges of sediment erosion • Jhimruk power plant can be considered a severe one in Nepal • Renewable Nepal project, KU and Water power Laboratory, NTNU has developing Matlab based software called Khoj • Khoj facilitates to produce preliminary design data for Francis turbine with accountability of sediment erosion • CFD and FSI analysis has greater roll on improvement of hydraulic machine design and performance analysis

4. International Conference on TIM, 2012, Nepal Runner blade Francis turbine Runner blade after one year of operation at Jhimruk Power plant, Nepal Stay vane, Scroll casing, runner inspection at Telva Power Plant Norway Runner assembly of Telva Power Plant Power plant

5. International Conference on TIM, 2012, Nepal Objectives • To analysis the impact of sand erosion on Francis turbine. • To identify the possible solution for the minimizing effect of erosion on turbine. • To innovate optimization on Francis Turbine design. • To design and develop new Francis turbine.

6. International Conference on TIM, 2012, Nepal Design of Francis runner • Khoj software generated the data in terms of guide curves, blade curves, hub curve erosion factor, Velocity components, characteristic parameters, turbine dimensions and corresponding domains for the CFD analysis • On the basis of data prevailed by the software, turbine blade, hub and shroud data were imported to Pro/Engineer software Hub Shroud 3D Runner Assembly Blade

7. International Conference on TIM, 2012, Nepal Core design process Basic design parameter for JHC Optimized values for P1-vel R and head-H

8. International Conference on TIM, 2012, Nepal Core design process Optimization Layout in ANSYS workbench

9. International Conference on TIM, 2012, Nepal Core design process Pressure distribution Pressure distribution R1 Blade R2 blade Velocity distribution

10. International Conference on TIM, 2012, Nepal Core design process Pressure distribution Pressure distribution R3 Blade R4 Blade R5 blade Velocity distribution

11. International Conference on TIM, 2012, Nepal Core design process • Optimized trade-off charts 1 Efficiency, head, Shaft power and Velocity component Vel-R

12. International Conference on TIM, 2012, Nepal Core design process • Optimized trade-off charts 2 Efficiency, Flow, Shaft Power and Velocity component Vel-R

13. International Conference on TIM, 2012, Nepal Core design process • FEM analysis Pressure distribution on top cover Pressure distribution on bottom cover

14. International Conference on TIM, 2012, Nepal Core design process • FEM analysis • FSI Analysis Guide vane Boundary condition location Stress distribution on runner Assembly

15. International Conference on TIM, 2012, Nepal Core design process (Vone Mess) Stress distribution on single blade (Vone Mess ) Stress distribution on blade assembly Deformation on runner

16. International Conference on TIM, 2012, Nepal Limitations • Optimization was performed only one set of blade profile. • FSI analysis was performed only on Francis turbine runner assembly. • During the FSI analysis, Unidirectional Coupling was chosen, considering there was no large deformation on runner.

17. International Conference on TIM, 2012, Nepal Results and Discussion • Optimization was performed on CFD that signifies reducing simulation and cost of design • Trade-off chart determines the trade-off points which is used to show the relation between variables • Pressure distribution and velocity at trailing were observed by using CFD analysis • R2 Blade was selected for FSI analysis since it has found uniform pressure distribution as well as relatively lower velocity • FEM analysis was performed on guide vane, upper and lower cover • Unidirectional coupled FSI analysis prevailed that total deformation of runner assembly was 0.00016931m which is safe for structural steel

18. International Conference on TIM, 2012, Nepal Conclusion and Recommendation • Erosion problem on Francis turbine due to sand laden water cannot be stopped completely by current technology but it can be minimized to the acceptable limit. • Use of FEM, CFD and FSI tool reduce the design process and simulation time meticulously. • New design processes found to be more sophisticated than the traditional way of design for the Francis turbine. • Simulated result predicted that the new design method can accommodate sand erosion problem in more sophisticated way. • It is recommended that simulation should be done in whole turbine unit and for better prediction two-way simulation is more reliable.

19. Recommendation • It is recommended that simulation should be done in whole turbine unit and for better prediction two-way simulation is more reliable. • Technological challenges and opportunities that recognize due to innovative design of Francis turbine should adopt by the turbine manufacturers.

20. International Conference on TIM, 2012, Nepal Thank you very much for your time and attention!!! Any queries???