Aerodynamic Study of a Small-Scale Wind

Turbine

Ing. Eduardo Barbier

Ing. Pablo Bucello

Dr. Sebastián D’hers

PRESENTATION TOPICS

• Case Study Description;

• Theoretical Aproximation;

• Numerical Simulation;

• Conclusion and next steps.

Case Study

Case Study :

•Small HAWT

•Nominal Power: 1100W @ 10m/s.

•Rotational Speed: 300 rpm.

• Control method: Mechanical furl (>9m/s).

•Diameter 3,3m.

•Installation Height: 9-13m

Objectives:

•Aerodynamic Study

•Theoretical Approximation.

•Numerical Simulation.

Theoretical Approximation

Theoretical Maximum Output Power : 3180W Betz Limit

Theoretical Estimation Mechanical Output Power: 2443 W BEM

Estimated Nominal Power: 1560 W

Mechanical Efficiency

0.8

Electrical Efficiency

0.8

CFD model

• ANSYS 14.5

– Meshing: ICEM CFD

– Pre-Solver/Solver: CFX

– Postprocessing: CFD-Post

2D Model 3D Model

1 x10^5 Elements 4x10^6 Elements

y+<1 y+<1

Spallart-Allmaras / K-Ω Spallart-Allmaras / K-Ω

2D Model

2D Mesh – Trailing Edge Sensibility

Lift / Drag coefficient dispersion < 5%

2D Model Results

•Difference between experimental and simulated results constrained under 10%.

•Small angles of attack error is below 5%

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

0.18

0.20

0 2 4 6 8 10 12 14 16 18 20 22

Angle of attack [deg.]

Dra

g c

oeff

icie

nt

Simulated

Experimental

0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

1.60

1.80

0 2 4 6 8 10 12 14 16 18 20 22

Angle of attack [deg.]

Lif

t co

eff

icie

nt

Simulated

Experimental

3D Model

Boundary Conditions

• Cyclic symmetry (only 1/3 of the WT is modeled).

• Column effects neglected.

• Structured mesh

• Rotating domain

• Steady State Analysis

Uniform

tangential speed

Cyclic Symmetry

Free slip wall

Free slip wall

Normal Speed

3D Model Results

3D Model Results

3D Model Results

•Simulation validated with experimental results

Conclusion and next steps

Conclusions

• 2D and 3D models developed for COSTA-1 wind turbine.

• Both models have good experimental correlation.

• Pressure and shear stress distribution in the blade is obtained.

Future Work

• Use pressure and shear distributions for blade structural analysis.

• Evaluate structural optimization: laminations schemes.

• Develop an FSI model

Acknowledgments