Wind turbine design through evolutionary algorithms based on surrogate CFD methods

An automatic design environment using evolutionary techniques has been developed for the design of Horizontal Axis Wind Turbine (HAWT) blades taking into account both the aerodynamics and the structural constraints of the blades. This design environment is based on a simple, fast, and robust aerodynamic simulator intended for the prediction of the performance of any turbine blade produced as an intermediate individual of the evolutionary search process. In order to reduce the computational costs, the results obtained by this simple simulator have been corrected through the application of Artificial Neural Network (ANN) based approximations. An additional stress analysis stage has been introduced in order to take into account the structural resistance of the blades as a constraint throughout the optimization process. Results of the simulations obtained using this technique, of the application of the automatic design procedure and of the performance of the wind turbines thus produced are presented. In a first test case the rotor designed through the proposed method is compared to the one obtained analytically for a given air speed. This comparison to an analytical optimum provides a good index in order to evaluate the performance of the method. In a second case the rotor is optimized for a typical wind speed distribution, which is a more realistic scenario where the cost performance of the resulting turbines needs to be evaluated.