Design of a VerticalAxis Wind Turbine MUN VAWT

Design of a Vertical-Axis Wind Turbine MUN VAWT DESIGN Group 11 Jonathan Clarke Luke Hancox Daniel Mac. Kenzie Matthew Whelan

Agenda Phase 1 Project Goals & VAWT Benefits Configuration Design Selection Phase 2 & 3 Aerodynamic Analysis Structural Analysis Mechanical Components Economic Analysis Image Credits: The Telegram

Problem Definition and Goals Problem Definition Design a VAWT for operation in remote communities in Newfoundland Labrador. The turbine should: Work in conjunction with diesel generators Simple design to reduce manufacturing costs and maintenance issues Produce at least 100 k. W of power at rated wind speed Able to account for variable wind conditions in the target area

Project Scope The project will examine the following aspects of the VAWT design: Detailed structural design and analysis Detailed aerodynamic simulation using computational fluid dynamics Basic vibrational analysis Modelling and engineering drawings of mechanical and structural components Economic analysis

Why a Vertical Axis Wind Turbine? Heavy drivetrain components are located at the base Easier to maintain They operate from winds in any direction No yaw system required Generate less noise than horizontal-axis turbines

Concept Selection: VAWT Configurations Two main configurations: Savonius and Darrieus Savonius is drag driven Low efficiency Darrieus is lift driven High efficiency

Concept Selection: VAWT Configurations X Two main configurations: Savonius and Darrieus Savonius is drag driven Low efficiency Darrieus is lift driven High efficiency

Concept Selection: Darrieus Configurations Complex Simple More Efficient Less Efficient H-Rotor Full Darrieus Helical

Concept Selection: Darrieus Configurations Complex Simple More Efficient Less Efficient H-Rotor Full Darrieus Helical

Concept Selection: Airfoil Profiles Extra thickness – increases blade strength Higher CL, Max for positive angles of attack

Concept Selection: Number of Blades Capital Cost Symmetrical Loading Torque Ripple

Concept Selection: Number of Blades Capitol Cost 3 Bladed Symmetrical Loading Torque Ripple

Concept Design Criteria Optimal Choice Configuration H-Rotor Darrieus Alternatives Full Darrieus, Helical Darrieus, Savonius # of Blades 3 2 to 4 Airfoil DU 06 -W-200 NACA-Series Airfoils

Aerodynamic Design Preliminary sizing: 320 m 2 swept area From wind power density formula: W /m 2 = ½ ρavg c. P V 3 Sizing Analytical analysis using QBlade Developed torque and power curve Validation using lift & drag equations Validation using ANSYS CFX Validation Fl = ½ ρavg A cl W 2

QBlade Results Cut-In Speed: 7 km/h Rated Power: 100 k. W @ 40 km/h Max Power: 130 k. W @ 50 km/h Cut-Out Speed: 94 km/h

ANSYS CFX Setup Used 2 D simulation Sacrifices some accuracy for reduced computational demand Sufficient to validate QBlade results Fine mesh near airfoils to capture boundary layer effects Mesh refinement study carried out

ANSYS CFX Results Average power: 145 k. W at peak operating condition Does not account for blade tip losses Sufficient to validate QBlade results

Dynamic Model Suitable under variable wind conditions Wind Speed Profile 15 14 13 12 11 10 9 8 0 2 4 6 8 10

Structural Design Composite Blade Design E-Glass Fibre and Epoxy Hollow Square Shape Wall Thickness: 50 mm Length: 20 m Fibreglass Layers: 386 Strut Design Hollow Cylindrical Shaft AISI 1045 Cold Drawn Steel Outer Diameter: 36 cm Inner Diameter: 28 cm Length: 7. 6 m

Structural Design Hub Column Design AISI 1045 Cold Drawn Steel Outer Diameter: 0. 6 m Inner Diameter: 0. 55 m Length: 8. 5 m Tower Design A 35 Structural Steel 8 meter lengths Outer Diameter: 3 m Inner Diameter: 2. 95 m

Vibrations At 40 RPM, the aerodynamic and centripetal forces alternate 3 times / cycle Operating Frequency (@ 40 RPM) = 2 Hz Maximum Vortex Shedding Frequency = 1. 3 Hz Component Natural Frequency Tower 3. 4 Hz Struts 2. 5 Hz Blades 3. 3 Hz Drive Shaft 283 RPM (critical speed)

Vibrations Struts Blades Tower

Mechanical Components Drive Shaft Outer Diameter: 406. 4 mm Inner Diameter: 355. 6 mm Length: 7 m Bearings Tapered Roller Bearing Bore: 406. 4 mm Outer Diameter: 546. 1 mm Life Span: >20 years Mechanical Coupling RB Flexible Coupling

Braking and Control Dynamic braking used to control speed in high winds Dissipates excess power through a network of resistors External-contact drum brakes used for shutdown Spring-applied, electrically released Fail-safe operation Compressed air starting system Cheap and reliable SIBRE Siegerland Bremsen Gmb. H

Generator Low-speed permanent-magnet generator Eliminates need for a gearbox Units are typically custom-built for specific applications Rated speed can be as low as 10 rev/min Sicme Motori Srl

Economic Analysis Estimated Capital Cost $425 000. 00 Quotes Maintenance Cost per year VAWT Turbine - $10 000. 00 Diesel Generators - $86 380. 00 Projected Fuel Cost of 2015 $3 630 967. 00 Payoff Period ~1 M dollars saved annually for an installation of 5 turbines 3 Years $

Future Work Full 3 D CFD analysis Structural Dynamic Model Foundation / Civil Work Control System Design Full Scale Testing

Conclusion Goal: Design a simple, robust vertical-axis wind turbine for use in remote communities Project goals were met VAWT design is a viable option to provide power to remote communities

MUN VAWT DESIGN ENGI 8926 Mechanical Design Project II QUESTIONS? http: //www. munvawtdesign. weebly. co m Acknowledgements: Thank you to Dr. Sam Nakhla for guidance on structural analysis.