Design of a Vertical-Axis Wind Turbine MUN VAWT DESIGN Group 11 Jonathan Clarke Luke Hancox Daniel MacKenzie Matthew Whelan
Feb 09, 2016
Design of a Vertical-Axis Wind TurbineMUN VAWT DESIGN
Group 11Jonathan ClarkeLuke HancoxDaniel MacKenzieMatthew 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
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
Low efficiency
Darrieus is lift driven High efficiency
Concept Selection: VAWT Configurations
Two main configurations: Savonius and Darrieus Savonius is drag driven
Low efficiency
Darrieus is lift driven High efficiency
X
Concept Selection: Darrieus Configurations
H-Rotor
Simple
Less Efficient
Complex
More Efficient
HelicalFull Darrieus
Concept Selection: Darrieus Configurations
H-Rotor
Simple
Less Efficient
Complex
More Efficient
HelicalFull Darrieus
Concept Selection: Airfoil Profiles
Extra thickness – increases blade strength
Higher CL,Max for positive angles of attack
Concept Selection: Number of Blades
Capital CostSymmetrical LoadingTorque Ripple
Concept Selection: Number of Blades
Capitol CostSymmetrical LoadingTorque Ripple3 Bladed
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
Fl = ½ ρavg A cl W2
Sizing
Validation
QBlade Results
Cut-In Speed:7 km/h
Max Power:130 kW @ 50 km/h
Cut-Out Speed:
94 km/h
Rated Power:
100 kW @40 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
0 2 4 6 8 108
9
10
11
12
13
14
15
Wind Speed Profile
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 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
Tower
Blades
Struts
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 $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
MUN VAWT DESIGNENGI 8926 Mechanical Design Project II
QUESTIONS?http://www.munvawtdesign.weebly.com
Acknowledgements:Thank you to Dr. Sam Nakhla for guidance on structural analysis.