Design of Airfoils for Wind Turbine...
Transcript of Design of Airfoils for Wind Turbine...
03 May, 2004 1DUWIND, section Wind Energy, Faculty CiTG
Design of Airfoils for Wind Turbine Blades
Ruud van Rooij([email protected])
Nando Timmer
Delft University of TechnologyThe Netherlands
03 May, 2004 2DUWIND, section Wind Energy, Faculty CiTG
Delft University of Technology13200 Bsc+ Msc students, 4750 employees
Delft University Wind Energy Research Institute(Coordinator: Section Wind Energy)
Faculties:• Civil Engineering and Geosciences (Wind Energy, Offshore)
http://www.windenergy.citg.tudelft.nl/home/flash/index.html
• Information Technology and Systems (Electrical group)
• Design, Engineering and Production (Systems &Control)
• Aerospace Engineering (Aero, Aeroelastics)
03 May, 2004 3DUWIND, section Wind Energy, Faculty CiTG
Section Wind Energy (Civil Engineering and Geosciences => Aerospace Engineering)
Aerodynamic research
- Facilities
open-jetwind tunnel research wind turbine
low speed wind-tunnel
03 May, 2004 4DUWIND, section Wind Energy, Faculty CiTG
Contents
• Background
• Design goals HAWT airfoils
• Design approach• Performance comparison
• Airfoil testing
• Effect on wind turbine power Cp
• Overview HAWT airfoils
03 May, 2004 5DUWIND, section Wind Energy, Faculty CiTG
Background
Operational area
High Cp80% of Energy
0.0
0.2
0.4
0.6
0.8
1.0
1.2
0.0 5.0 10.0 15.0 20.0 25.0
W inds speed (m /s)
Pow er
Variable RPMControl: Power restriction
High max. L/DAirfoil: Max. lift considerations
03 May, 2004 6DUWIND, section Wind Energy, Faculty CiTG
Background
Blade geometry
- High max. L/D- Insensitive to
roughness- Similar design
angle
Airfoil:
- High max. lift(Rot. Effects)
No Aerodynamicdemands
Outboard: t/= .15-18
Mid span: t/= .25
Inboard: t/> .30
Structural:
Transition piece
03 May, 2004 7DUWIND, section Wind Energy, Faculty CiTG
Background
Effect of rotation
RFOIL code
• Integral boundary layer eq.
• Extended for radial flow• Radial equations• Cross flow profile
parameter is c/r(= local solidity)
-0.50
0.00
0.50
1.00
1.50
2.00
2.50
-5.0 0.0 5.0 10.0 15.0 20.0 25.0
Angle (deg.)
cl
DU 91-W2-250Re = 3.0x10e6
2d
mid-span
inboard
Stall delay
03 May, 2004 8DUWIND, section Wind Energy, Faculty CiTG
Design goals HAWT airfoilssteady
Low noise
.21 >.28 - .21> .28Thickness-to-chord ratio
High maximum lift-to-drag ratio
Structural demands
Geometric compatibility
Insensitivity to roughness
Low max. and benign post stall
03 May, 2004 9DUWIND, section Wind Energy, Faculty CiTG
Design approach(example DU 91-W2-250)
DU 91-W2-250
NACA 63-425
Main features
S-Tail => Aft-loading
Small upper surface thickness => reduced roughness sensitivity
03 May, 2004 10DUWIND, section Wind Energy, Faculty CiTG
Design approach(pressure distributions DU 91-W2-250, Re = 3.0x106)
- 4. 0
- 3. 0
- 2. 0
- 1. 0
0. 0
1. 00.0 0.2 0.4 0.6 0.8 1.0x/c
Cp
Separation
Aft-loading
TransitionAlpha= 0.0o
7.0o
11.0o
Low roughness sensitivity=> Transition at nose for Cl_max
Low drag=> Aft transition at Cl_design
03 May, 2004 11DUWIND, section Wind Energy, Faculty CiTG
-0.50
0.00
0.50
1.00
1.50
0 50 100 150cl/cd
cl
-0.50
0.00
0.50
1.00
1.50
-5.0 0.0 5.0 10.0 15.0 20.0Angle (deg.)
cl
DU 91-W2-250
NACA 63-425Re = 3.0x106
Airfoil design(2d performance)
Design lift
Measurements at LST-TU Delft: Clean
03 May, 2004 12DUWIND, section Wind Energy, Faculty CiTG
-0.50
0.00
0.50
1.00
1.50
0 30 60 90cl/cd
cl
-0.50
0.00
0.50
1.00
1.50
-5.0 0.0 5.0 10.0 15.0 20.0Angle (deg.)
cl
DU 91-W2-250
NACA 63-425Re = 3.0x106
Airfoil design(2d performance)
Design lift
Measurements at LST-TU Delft: Roughness simulatedZZ-Tape at 5% u.s.
03 May, 2004 13DUWIND, section Wind Energy, Faculty CiTG
Airfoil testing(Low speed low turbulence tunnel)
Test section size 1.80 x 1.25 mMaximum speed 120 m/sTurbulence level 0.015% at 10 m/s
0.07% at 70 m/s
Test section
03 May, 2004 14DUWIND, section Wind Energy, Faculty CiTG
Airfoil testing(effect of leading edge thickness)
-0.4
0
0.4
0.8
1.2
1.6
-5 0 5 10 15 20 25 30 35 40
angle of attack (degrees)
Lift
coef
ficie
nt
Re=1.0x106
DU 97-W-300
DU 96-W-180
03 May, 2004 15DUWIND, section Wind Energy, Faculty CiTG
Airfoil testing(effect of high Reynolds numbers)
0.4
0.6
0.8
1.0
1.2
1.4
1.6
0 5 10Re x10-6
0
20
40
60
80
100
120
0 5 10Re x10-6
Clean
Zigzag tape 0.4 mm
Carborundum 60
Airfoil: DU 97-W-300Mod
(Cl/Cd)max Cl,max
03 May, 2004 16DUWIND, section Wind Energy, Faculty CiTG
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5
-50 0 50 100 150 200 250 300 350 400
angle of attack
Cl, Cd
DU 96-W-180
Re=700,000
Airfoil testing(360 degrees)
03 May, 2004 17DUWIND, section Wind Energy, Faculty CiTG
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5
-50 0 50 100 150 200 250 300 350 400
angle of attack
Cl, Cd
DU 96-W-180
Re=700,000
Airfoil testing(360 degrees)
α=24o
03 May, 2004 18DUWIND, section Wind Energy, Faculty CiTG
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5
-50 0 50 100 150 200 250 300 350 400
angle of attack
Cl, Cd
DU 96-W-180
Re=700,000
Airfoil testing(360 degrees)
α= 40o
Cl= 1.145
03 May, 2004 19DUWIND, section Wind Energy, Faculty CiTG
Airfoil testing(360 degrees)
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5
-50 0 50 100 150 200 250 300 350 400
angle of attack
Cl, Cd
DU 96-W-180
Re=700,000
α=90o
Cl= 0.10 Cd= 1.914
03 May, 2004 20DUWIND, section Wind Energy, Faculty CiTG
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5
-50 0 50 100 150 200 250 300 350 400
angle of attack
Cl, Cd
DU 96-W-180
Re=700,000
Airfoil testing(360 degrees)
α= 160o
Cl= -.627
03 May, 2004 21DUWIND, section Wind Energy, Faculty CiTG
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5
-50 0 50 100 150 200 250 300 350 400
angle of attack
Cl, Cd
DU 96-W-180
Re=700,000
Airfoil testing(360 degrees)
α= 194o
Cl= 0.541
03 May, 2004 22DUWIND, section Wind Energy, Faculty CiTG
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5
-50 0 50 100 150 200 250 300 350 400
angle of attack
Cl, Cd
DU 96-W-180
Re=700,000
Airfoil testing(360 degrees)
α= 224o
Cl= 0.811
03 May, 2004 23DUWIND, section Wind Energy, Faculty CiTG
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5
-50 0 50 100 150 200 250 300 350 400
angle of attack
Cl, Cd
DU 96-W-180
Re=700,000
Airfoil testing(360 degrees)
α= 270o
Cl= -0.11 Cd= 1.832
03 May, 2004 24DUWIND, section Wind Energy, Faculty CiTG
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5
-50 0 50 100 150 200 250 300 350 400
angle of attack
Cl, Cd
DU 96-W-180
Re=700,000
Airfoil testing(360 degrees)
α= 316o
Cl=- 0.971
03 May, 2004 25DUWIND, section Wind Energy, Faculty CiTG
Airfoil testing (aerodynamic devices)
• Stall strips Ø 1.2 mm
DU 93-W-210 R = 2.0x106
-1.0
-0.5
0.0
0.5
1.0
1.5
0.00 0.01 0.02 0.03cd
cl
-1.0
-0.5
0.0
0.5
1.0
1.5
-10 0 10 20α ( o)
cl
no trip wire
wire at 0.5%c l.s.
wire at 0.25%c l.s.
03 May, 2004 26DUWIND, section Wind Energy, Faculty CiTG
-0.4
0.0
0.4
0.8
1.2
1.6
2.0
0.0 30.0 60.0 90.0 120.0Cl/Cd
Cl
-0.4
0.0
0.4
0.8
1.2
1.6
2.0
-5.0 0.0 5.0 10.0 15.0 20.0 25.0Alpha (deg.)
Cl
VG at x/c= 0.2VG at x/c= 0.3Clean
DU 91-W2-250Re = 2.0x106
Airfoil testing (aerodynamic devices)
• Vortex generators
03 May, 2004 27DUWIND, section Wind Energy, Faculty CiTG
Effect on wind turbine performance(2d stationary performance)
Calculated optimal element performance at mid-span for TSR= 7.5
ZZ-tape 5% u.s.
CpLoadingCp_elem“Static load”Cl_max*c
L/D-maxc/RClean
-5.1%8%.532.155600.135DU 91-W2-250
-0.24%6%.560.1521190.119NACA 63-425
.212
0.143
0.149
.503
.561
.56
-10.2%48%390.212NACA 63-425
0%0%1250.105DU 91-W2-250
-0.06%4%1220.106AH 93-W-257
* “Static load” reference based on 1 year gust for fixed pitch blades
03 May, 2004 28DUWIND, section Wind Energy, Faculty CiTG
0.50
0.51
0.52
0.53
0.54
0.55
0.56
0.57
0 20 40 60 80 100 120 140max. L/D
local Aero Cp
Effect on wind turbine performance (2d stationary performance)
25% thick airfoil class (mid-span for TSR= 7.5)
“Rough”
DU 91-W2-250
-5%
NACA 63-425
-10%
03 May, 2004 29DUWIND, section Wind Energy, Faculty CiTG
Overview of HAWT airfoils
General aviation airfoils• NACA 63-4xx and NACA 63-6xx series• NACA 64-4xx
Dedicated airfoils• S8xx series (NREL, USA)
• FFA W-xxx (FOI, Sweden)
• Risø-A1-xxx (also B, P-series, Risø, Denmark)
• DU xx-W-xxx (Delft, Netherlands)
03 May, 2004 30DUWIND, section Wind Energy, Faculty CiTG
Overview of HAWT airfoils
• Overview of DU-airfoils and users
GE-Wind, REpower, Dewind, Suzlon, Gamesa, LM Glasfiber, NOI Rotortechnik, Fuhrlander, Pfleiderer, EUROS, NEG Micon, Umoe blades, Ecotecnia ……..
DU 97DU 97--WW--300300DU 96DU 96--WW--180180
DU 95DU 95--WW--180180
DU 93DU 93--WW--210210
DU 00DU 00--WW--212212DU 00DU 00--WW--350350
DU 91DU 91--W2W2--250250
03 May, 2004 31DUWIND, section Wind Energy, Faculty CiTG
Next steps:
Extending to all operational situations :
• Measurements => “high” Reynolds number=> chart unsteady behavior of DU airfoils
New airfoil designs :
• Very thick airfoils for lightweight blades
• Control of rpm only => Low TSRLow Cl-max, benign stall
=> High TSRLow drag
• Aero-elastic tailoring => Dynamic airfoil design(Probably low Cl-max)