Aerodynamic Performance Optimization Of Horizontal Axis Wind Turbine Airfoil

Wind turbine blade is the core component of wind turbine to obtain wind energy,and airfoil,as the basic element of blade composition,is the main factor to determine the performance of the blade.Therefore,the optimization research of wind turbine airfoil has important engineering practical significance.The main work is as follows:(a)Research on wind turbine airfoil optimization based on Adjoint AlgorithmsTo improve the airfoil lift-drag ratio,the simulation and optimization research has been performed on the traditional aviation airfoil NACA0012 and the wind turbine airfoil S8036 respectively under the condition of low wind speed,which are always used in horizontal axis wind turbines.Based on the CFD(Computational Fluid Dynamics)numerical simulation,the Adjoint method(based on the control theory)and the fast mesh deformation methods are employed during the research.Results show that two kinds of airfoils'aerodynamic characteristics could be improved effectively by combining the Adjoint method(based on the control theory)and the fast mesh deformation methods.Compared with the original airfoils of NACA0012 and S8036,lift-drag ratios of optimized airfoils were increased by 8.75%and 16.74%respectively under the same flow field conditions.(b)Research on wind turbine airfoil optimization based on Multi-Island Genetic AlgorithmsAiming at the problem that the Hicks-Henne function can not change the trailing edge thickness of blunt trailing edge airfoil,a new trailing edge perturbation function is proposed to improve the original function.With the optimization object of improving the airfoil lift-drag ratio,the Isight software platform is used to integrate the self-compiled key points' coordinates generation program,the CFD calculation software and the Multi-Island Genetic Algorithms to establish the airfoil optimization cycle.And the NACA0012 airfoil is used as the reference airfoil for the aerodynamic optimization research of comparing and analyzing the influence of Hicks-Henne function airfoil parameterization method before and after the improvement on the airfoil aerodynamic optimization results.Results show that:compared with the original airfoiL the lift-drag ratio of the optimized airfoil increases by 14.0%and 15.8%respectively.Besides.the airfoils optimized by Adjoint Algorithms and Multi-Island Genetic Algorithms are compared and analyzed.(c)Comparative analysis of the two optimization algorithmsTaking the optimization calculation result of NACA0012 airfoil as an example,the calculation amount of the Adjoint Optimization Algorithms is only one-hundred as much of that of the Multi-Island Genetic Algorithms,while the lift-drag ratio is only 8.75%higher than that of the original airfoil.However,the lift-drag ratios of the optimized airfoil obtained with the Multi-Island Genetic Algorithms are 14.0%and 15.8%higher than that of the initial airfoil respectively.The main reason for the large differences between the optimization results is that the influence of the airfoil's leading edge thickness change on the lift-drag ratio couldn't be reflected in the optimization research with the Adjoint method.