Optimization Design And Performance Analysis Of Horizontal-Axis Wind Turbine Airfoil Based On Kriging Model

Wind power generation has been developing rapidly due to the advantages of mature technology,low development cost,low environmental pollution and wide distribution of wind energy resources.The power generation efficiency of wind turbine is largely determined by the aerodynamic characteristics of the wind turbine.The blade is the main component of the wind turbine wind wheel,the airfoil as the basis of blade aerodynamic shape design,its performance will directly affect the aerodynamic characteristics of the wind wheel.Therefore,in order to improve the wind turbine blade wind energy capture capacity and wind turbine generator power generation efficiency,the design of wind turbine special airfoil with better aerodynamic performance is of great significance.At present,China’s independent research and design of wind turbine airfoil is less mature than the development of foreign wind turbine airfoils.Therefore,the research on the design of wind turbine airfoil can further promote the improvement of China’s independent intellectual property rights in the field of wind power,which has important research significance and engineering practical value.To address this problem,this paper proposes to combine the high-precision numerical simulation method and the optimization design method to carry out the research on the special airfoil design of horizontal axis wind turbine.Firstly,Poisson’s equation is solved to generate a high-quality airfoil mesh,and on this basis,a kinematic nested mesh system is constructed to satisfy the non-constant flow field solution of the wind turbine by combining the background mesh.To improve the computational efficiency of the flow field solution,the implicit LU-SGS method is used for the time discretization and the Roe-MUSCL format with third-order accuracy is chosen for the spatial discretization.To accurately capture the separated flow,the turbulence model adopts the SST k-ω turbulence model to solve the turbulent viscosity;to meet the lowspeed condition in the wind turbine airfoil calculation,the convergence speed and computational accuracy of the flow field calculation are improved by introducing the low-speed preprocessing matrix.By coupling Kriging model,genetic algorithm and CFD method to establish the wind turbine airfoil optimization design level,the airfoil parameterization in the optimization process adopts the CST method with 7th order Bernstein polynomial.The optimized aerodynamic shape design is based on the classical S809 airfoil with the maximum lift-to-drag ratio and the maximum tangential force coefficient as the objective functions for the operating conditions and performance requirements of the airfoil.The numerical calculation results show that the lift coefficient of the optimized airfoil increases by 9.68% and 8.57%,and the drag coefficient decreases by 0.84% and 2.01% under the two design states of 6° and 8°,respectively,and the corresponding lift-to-drag ratio increases by 10.34% and 10.75%,respectively.S809 airfoil.To verify the applicability of the optimized airfoil in wind turbine design,a threeblade wind turbine was designed based on the optimized airfoil and S809 airfoil respectively,and the comparative analysis of the wind turbine aerodynamic performance under different operating conditions was carried out in this paper.The calculation results show that the CP value of the wind turbine blade based on the optimized airfoil design increases by 7.5% and the CQ value increases by 5.88% under the design wind speed condition.In the non-design wind speed condition,the CP value of the wind turbine blade based on the optimized airfoil design increases by 8.64% and 10.53%,and the CQ value increases by 21.15% and 22.22%,respectively.In order to verify the aerodynamic characteristics of the optimized airfoil more comprehensively,the paper finally verifies the aerodynamic performance of the wind turbine blade under yaw conditions.It also proves that the optimized airfoil can maintain good performance under yaw conditions,which fully reflects the practical application value of the optimized airfoil designed in this paper.