1. DESIGN OF AIRFOILS FOR WIND TURBINE BLADES Presented by Parezanovic Vladimir Faculty of Mechanical Engineering Belgrade University

2. The Objectives Simulate the airflow around selected well- known airfoils Obtain sufficient level of agreement between experimental and simulated data Introduce “Virtual Prototyping” into the design process

3. The process Importing or designing the geometry Generating the mesh Computational model setup Iteration and monitoring Results Post-processing

4. Geometry and airfoils Geometry is designed or imported Airfoils investigated:  NACA 63(2)215  FFA-W3-211  A-Airfoil

5. Mesh generation The resolution of the mesh can affect computations in many ways, most important are:  Accuracy  Computing time Some facts about mesh used:  Around 14000 elements  160 elements on the airfoil  Quadrilateral shaped cells  Cell size varies from 0.002 m 2 up to 1.6 m 2

6. Flow conditions Conditions corresponding to those in wind tunnel experiments:  Low Reynolds number (1.8 - 3.0x10 6 )  Free flow velocities around 25m/s  Low turbulence intensity

7. Numerical model What kind of flow is modeled? To what level of approximation? What is expected to happen? Setup in this case: For NACA 63(2)215 and FFA-W3-211 model is fully turbulent Laminar/turbulent transition modeled for A-Airfoil k-ω SST turbulence model is used in all cases

8. Lift and pitching moment coeff. curves (left), Drag coefficient curve (right) (A-Airfoil) A-Airfoil Lift and pitching moment coeff. curves (left), Drag coefficient curve (right) NACA63(2)215 NACA63(2)215 Results Lift and pitching moment coeff. curves (left), Drag coefficient curve (right) (FFA-W3-211) FFA-W3-211

9. Interpretation Simulation results agree with experimental data to within 10% The model is more exact for airfoils less susceptible to laminar/turbulent transition effects Lift easier to predict than drag A model with the ability to predict laminar/turbulent transition is needed

10. So, you’ve gotten your results… Then what?

11. What was all this about? MONEY! EFFICIENCY ENVIRONMENT

12. QUESTIONS?