Innovative Design of Francis Turbine for Sediment Laden Water Krishna Prasad Shrestha 1 Bhola Thapa 1, Ole Gunnar Dahlhaug 2 Hari P. Neopane 1 Biraj Singh

Innovative Design of Francis Turbine for Sediment Laden Water

Krishna Prasad Shrestha1

Bhola Thapa1,

Ole Gunnar Dahlhaug2

Hari P. Neopane1

Biraj Singh Thapa1

1Dept. Mechanical Engineering, Kathmandu University,

P.O. Box 6250, Dhulikhel, Nepal2 Dept. Energy&Process Engineering, Norwegian

University of Science and Technology,

NTNU, Trondheim, 7491, Norway

Email: [email protected]

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

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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

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Runner blade

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Francis turbine Runner blade after

one year of operation at Jhimruk

Power plant,Nepal

Runner assembly of Telva Power Plant Power plant

Stay vane, Scroll casing, runner inspection at Telva Power Plant Norway

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.

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Design of Francis runner

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• 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 AssemblyBlade


Core design process

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SN Parameters Value Unit1 Net design head(H) 201.5 m2 Net discharge per unit(Q) 2.35 m3/s3 Runner efficiency() 96 %

Basic design parameter for JHC

SN P1 P3 P4 P5 P6 P7

1 0.24 183.794 4084080 94.696 2.35706 104.72

2 0.2 218.972 4882860 93.4553 2.35706 104.72

3 0.28 160.439 3486090 93.0557 2.35706 104.72

4 0.22 199.2 4454800 94.5628 2.35706 104.72

5 0.26 171.097 3761720 94.0276 2.35706 104.72

Optimized values for P1-vel R and head-H


Core design process

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Optimization Layout in ANSYS workbench


Core design process

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Pressure distribution


R1 Blade

R2 blade

Velocity distribution


Core design process

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R3 Blade

R4 Blade

R5 blade

Velocity distribution


Core design process

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Efficiency, head, Shaft power and Velocity component Vel-R

• Optimized trade-off charts 1

Core design process

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• Optimized trade-off charts 2

Efficiency, Flow, Shaft Power and Velocity component Vel-R


Core design process

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• FEM analysis

Pressure distribution on top cover

Pressure distribution on bottom cover


Core design process

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• FEM analysis• FSI Analysis

Guide vane Boundary condition location

Stress distribution on runner Assembly


Core design process

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Deformation on runner

(Vone Mess ) Stress distribution on blade

assembly

(Vone Mess) Stress distribution on single

blade


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.

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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

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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.

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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.

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Thank you very much for your time and attention!!!

Any queries???

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Documents

Innovative Design of Francis Turbine for Sediment Laden Water Krishna Prasad Shrestha 1 Bhola Thapa 1, Ole Gunnar Dahlhaug 2 Hari P. Neopane 1 Biraj Singh