Effect of airfoil and composite layer thicknesses on an aerostructural blade optimization for wind turbines

The purpose of this research is to enhance the performance of wind turbine blades by exploring the effect of adding airfoil and material layer thicknesses to the optimization design process. This is accomplished by performing an aerostructural blade optimization to minimize mass over annual energy production and thereby reduce the cost of energy. Changing airfoil thickness allows the airfoil shape to evolve as part of the optimization. The airfoil thicknesses are allowed to vary within two airfoil families, the TU-Delft and NACA 64-series, that are used in the NREL 5-MW reference turbine. Both experimental wind tunnel and computational data are used to estimate the blade's aerodynamic performance. Material layer thicknesses in the composite lamina spar cap and trailing edge panels are separated and added to the optimization. Results show a reduction of 0.8% in the full optimization as compared to the reference turbine due to an increase in energy production (+0.6%) and decrease in blade mass (-2.7%).