Transcript Wind Turbine Design - [ jackness.atomtbomb.com ]

AAE 415 – Aerodynamic Design
Final Project Presentation
Large Horizontal-Axis
Wind Turbine Design
Ted Light
Jeff Robinson
December 13, 2003
Outline
• Background
– Wind Energy & History
– Types of Wind Turbines
– Wind Turbine Aerodynamics
• Design Process
– Starting Point and Analysis Method
• Results
Wind Energy & History
•
Wind energy has been used
for thousands of years, for
sailing, pumping water,
grinding grain, etc.
•
In the early 1900s, wind
turbines were used to
produce direct electric
current to small areas
•
Oil Crisis of 1970s renewed
interest in wind turbines as a
cheap, clean, unlimited
source of energy
Types of Wind Turbines
“Darrius” Vertical
Axis Wind Turbine
Large Horizontal
Axis Wind Turbine
Traditional Windmill
Airfoil Aerodynamics
Rotation = r * W
Relative Wind = W
a
Wind = V0
• Wind Speed and Turbine Rotation must be
combined to find total velocity that airfoil sections
“see”
Desired Airfoil Qualities
For a fixed-pitch, constant speed machine,
recommended airfoil qualities at 0.75R are:
– High L/D
– Low clmax near tip reduces tendency to
overpower generator in high wind speeds
– Insensitive to surface roughness (bugs, birds,
bullets)
Design Process
• CMARC used to analyze designs
• Existing wind turbine with known geometry
and performance modeled for baseline
comparison
• Assumed constant velocity generator
(Power) = (Moment)*(Rotation Rate)
• Variation and Analysis of Designs
– Geometric parameters modified
Analysis Strategy
• Start with an existing wind turbine, then
modify its geometry
• Geometry varied
– Airfoil section
– Twist distribution
– Chord distribution
• Rotational rate, number of blades and
span were held constant
Mod-2 Wind Turbine
• Manufactured by Boeing in late 1970s
• Development sponsored by NASA
Mod-2 Wind Turbine Specifications
13.7 m
1.43 m
3.45 m
45.7 m
•
•
•
•
•
•
Diameter = 91.4 m
No. of Blades = 2
Average Wind Speed = 12.5 m/s
Rotation Rate = 17.5 rpm
Airfoil: NACA 23024
Power Output = 2.5 MW
CMARC Inputs
• Rotation rate about x-axis set to that of
Mod-2 wind turbine (17.5 rpm)
– Many wind turbines are “constant speed”
• Wind Speed set to local average wind
speed for Mod-2 (12.5 m/s)
• Baseline geometry emulated Mod-2
geometry, then varied
Results
Model #
Description
Mod-2
Mod-A
Mod-B
Mod-C
Mod-D
Mod-E
Mod-F
Mod-G
Mod-H
Mod-I
Mod-J
Mod-2 Rating
r/R
0
0.25
0.5
0.75
1
Baseline Model
Airfoil Changed to NACA 651-012
Airfoil Changed to NACA 65-410
Airfoil Changed to Althaus AH 93-W-145
Chord Change (1) from Mod-B with no sweep
Chord Change (2) from Mod-B with no sweep
Chord Change (3) from Mod-B with no sweep
Chord Change (3) from Mod-B with sweep
Twist Change (1) from Mod-G
Twist Change (2) from Mod-G
Twist Change (3) from Mod-G
Published Power Rating
Chord Changes
(1)
(2)
15
14
11.4
11.4
5.7
7
3.8
3.8
2.85
2.85
(3)
10
8
6
4
2
Power (kW)
5816
5516
6179
2551
8914
8442
7872
9380
10367
7849
7735
2500
D from
Baseline
---12%
15%
-131%
124%
105%
82%
143%
182%
81%
77%
Twist Changes (values in deg from wind axis)
r/R
(1)
(2)
(3)
0
6.1
6.0
5.5
0.25
66.7
27.8
83.5
0.5
83.4
49.5
89
0.75
93.8
71.3
90
1
111.6
93.0
92
Results
r/R
0
0.25
0.5
0.75
1
Chord (m)
10
8
6
4
2
Twist (deg)
6.1
66.7
83.4
93.8
111.6
Blade Tip
Leading Edge
Airfoil NACA 65-410
Root Section
Cp Distribution
Wake
for
Best
Blade
Results
Questions?