Efficiency of a VAWT with
Airfoil Pitch Control
Junkun Ma1, Cris Koutsougeras2, Hao Luo2
October 6, 2016
1Sam Houston State University
2Southeastern Louisiana University
VAWT and HAWT
VAWT: Vertical Axis Wind Turbine
HAWT: Horizontal Axis Wind Turbine
Advantages and Disadvantages
Advantages:
• Easier to install and maintain
• No need to point into the wind
• Low risk for human or birds
• Can be installed in urban area
Disadvantages:
• Stall start
• Low efficiency
• Dynamic stability: vibration and noise
• Pulsatory torque
VAWT with Pitch and Camber
Controls
Governing Equations
Low speed laminar flow: Navier – Stokes equations
High speed turbulent flow: k - e turbulent flow model
Force and Torque
Force:
Torque:
NACA 0012 Airfoil
COMSOL CFD Model
Velocity Field
Pressure Field
Torque at 300 Support Arm Angle
35000
37000
39000
41000
43000
45000
47000
49000
51000
0 20 40 60 80 100 120 140 160 180
To
rqu
e (
N)
Attack Angle (0)
Effects of Wind Speed
72000
74000
76000
78000
80000
82000
84000
0 20 40 60 80 100 120 140 160 180
To
rqu
e (
N)
Attack Angle (0)
5m/s
10m/s
15m/s
20m/s
Effects of Support Arm Angle
0.0
10000.0
20000.0
30000.0
40000.0
50000.0
60000.0
70000.0
80000.0
90000.0
0 20 40 60 80 100 120 140 160 180
Effects of Support Arm Angle
0.0
10000.0
20000.0
30000.0
40000.0
50000.0
60000.0
70000.0
80000.0
90000.0
0 20 40 60 80 100 120 140 160 180
Effects of Support Arm Angle
0.0
10000.0
20000.0
30000.0
40000.0
50000.0
60000.0
70000.0
80000.0
90000.0
0 20 40 60 80 100 120 140 160 180
Conclusions
• Torque with respect to the VAWT main rotor
shaft depends on wind angle of attack and
support arm angle
• Wind speed does affect the peak torque. But the
torque increase due to higher wind speed is
insignificant
• For the NACA 0012 airfoil, the torque always
peaks out at 90 degree angle of attack at any
given support arm angle
Future Work
• 2D multi-blades model
• 3D model to explore airfoil edge effect
• 3D multi-blades model
• Non-symmetric airfoil other than NACA 0012
Questions?