Turbine gió
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Wind Turbine
Wind Turbine
Blade Design
Blade Design
Classroom Activities for
Classroom Activities for
Wind Energy Science
Wind Energy Science
Joseph Rand
Joseph Rand
Program Coordinator
Program Coordinator
The Kidwind Project
The Kidwind Project
877-917-0079
877-917-0079
What is KidWind?
What is KidWind?
The KidWind Project is a team of teachers, students, engineers and
practitioners exploring the science behind wind energy in classrooms
around the US. Our goal is to introduce as many people as possible to
the elegance of wind power through hands-on science activities which
are challenging, engaging and teach basic science principles.
Orientation
Turbines can be categorized into two overarching classes
based on the orientation of the rotor
Vertical Axis Horizontal Axis
Calculation of Wind Power
•
Power in the wind
Power in the wind
–
Effect of swept area, A
–
Effect of wind speed, V
–
Effect of air density, ρ
R
Swept Area: A = πR
2
Area of the circle swept
by the rotor (m
2
).
Power in the Wind = ½ρAV
3
Number of Blades – One
•
Rotor must move more
rapidly to capture same
amount of wind
–
Gearbox ratio reduced
–
Added weight of counterbalance
negates some benefits of lighter
design
–
Higher speed means more noise,
visual, and wildlife impacts
•
Blades easier to install
because entire rotor can be
assembled on ground
•
Captures 10% less energy
than two blade design
•
Ultimately provide no cost
savings
Number of Blades - Two
•
Advantages &
disadvantages similar to
one blade
•
Need teetering hub and
or shock absorbers
because of gyroscopic
imbalances
•
Capture 5% less energy
than three blade designs
Number of Blades - Three
•
Balance of
gyroscopic forces
•
Slower rotation
–
increases gearbox &
transmission costs
–
More aesthetic, less
noise, fewer bird
strikes
Blade Composition
Wood
Wood
–
Strong, light weight,
cheap, abundant,
flexible
–
Popular on do-it
yourself turbines
•
Solid plank
•
Laminates
•
Veneers
•
Composites
Blade Composition
Metal
•
Steel
–
Heavy & expensive
•
Aluminum
–
Lighter-weight and easy
to work with
–
Expensive
–
Subject to metal fatigue
Blade Construction
Fiberglass
•
Lightweight, strong,
inexpensive, good fatigue
characteristics
•
Variety of manufacturing
processes
–
Cloth over frame
–
Pultrusion
–
Filament winding to produce
spars
•
Most modern large turbines
use fiberglass
Large Wind Turbines
•
450’ base to blade
•
Each blade 112’
•
Span greater than 747
•
163+ tons total
•
Foundation 20+ feet deep
•
Rated at 1.5 – 5 megawatt
•
Supply at least 350 homes
