Aerodynamic optimization of wind turbine with optimal circulation distribution based on full free vortex wake model

Through optimization of the blade bound circulation distribution, a fast aerodynamic optimization method for blade of wind turbine was developed. In the method, the full free vortex wake model was introduced, and then computed quickly by parallel processing and fast multipole method(FMM). When selecting Fourier series representation of the bound circulation as the optimization variables to decrease the number of optimization variables, using the power coefficient as an objective function and adding the thrust coefficient as a constraint, optimization was carried out and optimal blade geometry parameters were obtained from optimal circulation distribution. This was validated through comparisons with the National Renewable Energy Laboratory (NREL) experimental rotor. Results show that, when tip speed ratio was 3.79 and 4.74, with a thrust coefficient constraint, optimization could enhance the power coefficient by 32% and 8%, respectively. When a variety of blade numbers and tip speed ratios were chosen, without a thrust constraint, global optimizations were performed, and the power coefficients are over 0.48.