Transcript File - MUN VAWT DESIGN


Design of a Vertical-Axis Wind Turbine
MUN VAWT DESIGN
Group 11
Jonathan Clarke
Luke Hancox
Daniel MacKenzie
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
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
Concept Selection: Darrieus Configurations
Simple
Complex
Less Efficient
H-Rotor
More Efficient
Full Darrieus
Helical
Concept Selection: Darrieus Configurations
Simple
Complex
Less Efficient
H-Rotor
More Efficient
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
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:
W/m2
= ½ ρavg cP V3
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 W2
QBlade Results
Cut-In
Speed:
7 km/h
Rated
Power:
100 kW @
40 km/h
Max Power:
130 kW @
50 km/h
Cut-Out
Speed:
94 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
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
 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

$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 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.