Numerical and Experimental Analysis of Performance and Aerodynamic Loads on HAWT Blade

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Numerical and Experimental Analysis of
Performance and Aerodynamic Loads on HAWT Blade

• AeroAcoustics Noise Control Laboratory, Seoul
  National University
• Jiwoong Park, Hyungki Shin, Hogeon Kim, Soogab Lee

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Contents
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Introduction
Wind Tunnel Test
Free Wake Analysis
Analysis Validation
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Numerical models

• Vortex wake model
• engineering models based on vortex methods
• solved velocity potential expressed by Laplace
  Eqn.
• application of Biot-Savart law
• Free wake model or prescribed wake model
• currently proper model to solve aerodynamic
  loading
• added 3-d adjustment at stall region

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Free Wake model
CVC (Constant Vorticity Contour) Wake Structure
Vortex sheet trailing from the interval (ra,rb)
is replaced by a single vortex filament of
constant strength
Ref. NASA Contractor Report 177611
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Free Wake Model
Finite Vortex Element Free wake model
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Free Wake model
NREL test model
FVE free wake model
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STALL DELAY MODEL
Corrigan Stall delay model
Du Selig Stall delay model

• Corrected Aerodynamic Coefficient

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Flow Chart
pre-processor
Main-processor
post-processor
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NREL Wind Tunnel Test

• NASA AMES WIND TUNNEL
• Test section 25m ? 36m

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SNU Wind Tunnel Test

• KAFA WIND TUNNEL
• Test section 2.45m ? 3.5m

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Wake Analysis
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Wake Analysis
Tip Vortex Measurement by Hot Wire Probe
Ref. TU-Delft wind tunnel test
Butterworth 5th order filter Average of 3
Revolution
Raw data
Filtered data
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Wake Analysis
Tip Vortex Measurement by Hot Wire Probe
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Wake Analysis
Validation of FVE Free Wake model

• SNU model
• FVE Free wake vs measured trajectory

Measurement data of SNU model
FVE free wake geometry
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Wake Analysis
Validation of FVE Free Wake model

• Wind speed 13m/s

13m/s, TSR6.0, Yaw 10 deg.
Yawed flow case(10deg)
Wake geometry( TSR 6.5, 6.0 )
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Wake Analysis
Tip Vortex Pitch Angle

• SNU model
• FVE Free wake VS measured data

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Load Analysis (Head-on Flow Case)
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Comparison of predictions to NREL measurement data
Wake Geometry and Normal force distribution of
NREL BLADE

• FVE Wake Model
• 13m/s, TSR3.0

Circulation and Normal force distribution
Wake geometry
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Comparison of predictions to NREL measurement data
Shaft Torque

• FVE Free wake model
• apply stall delay model

3000
2500
2000
1500
1000
Torque (Nm)
500
0
5
10
15
20
25
-500
-1000
wind speed (m/s)
NREL
free wake with 2d table
free wake with Corrigan stall delay model
free wake with Du Selig stall delay model
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Comparison of predictions to NREL measurement data
Normal Force Coefficient
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Comparison of predictions to SNU measurement data
Wake Geometry Cn distribution of SNU BLADE

• Curved Vortex vs FVE Wake Model
• 14 m/s, TSR5.5

Curved vortex
FVE Free Wake
Wake Geometry
Cn distributions
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Comparison of predictions to SNU measurement data
Shaft Torque Comparison

• Curved Vortex vs FVE Wake Model
• 14 m/s, TSR5.5

Shaft Torque Distribution
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Load Analysis (Yawed Flow Case)
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Comparison of predictions to NREL measurement data
Wake Geometry of NREL BLADE

• Curved Vortex vs FVE Wake Model
• 15 m/s, TSR2.6
• Yaw angle 30 degree

Curved vortex
FVE Free Wake
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Comparison of predictions to NREL measurement data
Normal Force Coefficient distribution

• 15 m/s, TSR2.6
• Yaw angle 30 degree

r/R 0.47
r/R 0.3
r/R 0.63
r/R 0.80
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Comparison of predictions to SNU measurement data
Wake Geometry Cn distribution of SNU BLADE

• Curved Vortex vs FVE Wake Model
• 14 m/s, TSR5.5
• Yaw angle 30 degree

• Curved Vortex vs FVE Wake Model
• 14 m/s, TSR5.5
• Yaw angle 10 degree

FVE Free Wake
FVE Free Wake
Curved vortex
Curved vortex
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Comparison of predictions to SNU measurement data
Shaft Torque Comparison

• SNU Model
• Yawed Flow
• TSR5.5

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Concluding Remarks
Wake Analysis

• FVE free wake model is devised and validated
• Wake shape shows good agreement with measured
  geometry

Load Analysis

• Validated by NREL and SNU model
• Importance of the Wake-Tower interaction
• Effectiveness of FVE free wake model

Future work

• Refine free-wake model
• Dynamic stall delay model
• Aero-elastic model
• Noise prediction model