Christopher Kelley - National Rotor Testbed Design
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National Rotor Testbed Design Christopher L. Kelley Sandia National Laboratories st August 6
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Transcript of Christopher Kelley - National Rotor Testbed Design
National Rotor Testbed DesignChristopher L. KelleySandia National Laboratories31st August 2016
Motivation• To better understand wind turbine wakes• Use SWiFT experimental facility
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Aerodynamic Objective• Design wind turbine blades to be manufactured and flownfor research on wakes in an array• Create same initial conditions velocity/momentum deficit atrotor plane as fullscale machine• What shape does the blade need to produce scaled wake?
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A Scaled Wake
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How Is a Wake Created?
Γ′( rR
)=
Γ( rR)
RU∞=Cl
2
W
U∞
c
R
• Circulation isproportional to lift• Lift forces determineshed circulation
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Objective Function, Γ′fs
• most common wind turbine in USA, GE 1.5sle, GE37c• full-scale turbine model provided by manufacturer• modeled in WT_Perf• λ = 9
• smooth surface airfoil data from wind tunnel
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Objective Function, Cl
• for a given circulation, Cl determines local solidity• adequate stall margin• efficient L/D• smooth chord and twist distribution• Cl = 0.6
Γ′( rR
)=Cl
2
W
U∞
c
R
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Airfoil Selection Criteria
• Rec ≈ 2,000,000• high quality, public, and low turbulence wind tunnel data• fixed transition, roughness, and unsteady data• roughness insensitivity• thickness requirements
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Airfoil SelectionS814 ( tc = 0.24) and S825 ( tc = 0.17)
Cd
0 0.01 0.02 0.03
Cl
-0.2
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
S825 Re 1E6S825 Re 2E6S825 Re 3E6S825 Re 4E6S825 Re 6E6S814 Re 0.7E6S814 Re 1E6S814 Re 1.5E6S814 Re 2E6S814 Re 3E6
, [deg]-5 0 5 10 15 20
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Inverse Design
• created inversedesign tool• solved for chord andtwist• iterate with WT_Perf
RMSE Γ
0.08 0.085 0.09 0.095 0.1
RM
SE
α
0
0.2
0.4
0.6
0.8
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Circulation
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Geometry
r/R
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
c/R
0
0.05
0.1
subscale
V27
CPmax
r/R
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
β [
de
g]
0
5
10
15
subscale
V27
CPmax
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NRT Blade
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NRT Blade
(nrtu3d.u3d)
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Performance
Wind speed (m/s)4 6 8 10 12 14
Pow
er
(kW
)
0
20
40
60
80
100
120
140
160
180
200
Wind speed (m/s)4 6 8 10 12 14 16
β (
deg)
0
2
4
6
8
10
12
X: 11.11Y: 195
X: 7.65Y: 63.97
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Performance
D [m] λR2 σ [%] Prated [kW] CPR2CTR2
Pr(R2) Pr(R2.5) Pr(R3) cf AEP [GWh]
27 9 6.4 195 0.462 0.863 0.49 0.30 0.05 0.30 0.51
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Free Wake Vortex Simulation
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Momentum Recovery
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3D CFD, 11 m/s
2D BEMT agrees with 3d CFD separation location
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3D CFD3D flow effects and uncertainty of root section performance notan issue
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3D Printed Blade Mold at Oakridge
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Conclusions
• inverse design tool implemented to design blades toproduce a specific wake• blade geometry creates scaled wake of commercial 1.5 MWturbine• 3D CFD indicates no issues in using 2D for blade root forthis design• NRT blade to be flown at SWiFT and used for wakeexperiments
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