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

Agenda Phase 1 Phase 2 & 3 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 Design a VAWT for operation in remote communities in Newfoundland and Labrador. The turbine should: Work in conjunction with diesel generators Simple design to reduce manufacturing costs and maintenance issues Produce at least 100 kW 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 Darrieus is lift driven Low efficiency High efficiency

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

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

Concept Selection: Darrieus Configurations Simple Complex Less Efficient More 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 Symmetrical Loading Torque Ripple 3 Bladed

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

Aerodynamic Design Preliminary sizing: 320 m2 swept area From wind power density formula: Analytical analysis using QBlade Developed torque and power curve Validation using lift & drag equations Validation using ANSYS CFX W/m2 = ½ ρavg cP V3 Sizing Validation Fl = ½ ρavg A cl W2

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

ANSYS CFX Setup Used 2D 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 kW at peak operating condition Does not account for blade tip losses Sufficient to validate QBlade results

Dynamic Model Suitable under variable wind conditions

Structural Design Composite Blade Design Strut 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 Tower Design AISI 1045 Cold Drawn Steel Outer Diameter: 0.6 m Inner Diameter: 0.55 m Length: 8.5 m Tower Design A35 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 GmbH

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 Maintenance Cost per year $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 ~1M dollars saved annually for an installation of 5 turbines 3 Years

Future Work Full 3D 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

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