Research On Optimization Of Aerodynamic And Structural Performance Of Wind Turbine Blade

With the continuous improvement of wind turbine power,the blade size is becoming larger and larger,and the aerodynamic performance and strength requirements of the blade are also increasing.Blades account for about 25% of the whole wind turbine cost,the optimization of blades can effectively improve the generating capacity and increase its reliability.The design of blade can be divided into aerodynamic design and structural design,the design must meet the multi-objective requirements,such as good aerodynamic performance,lightest weight,lowest cost,resistance to extreme and fatigue loads,and limitation of tip displacement.The multi-level optimization of wind turbine blade is studied in this thesis,corresponding optimization methods are proposed for the aerodynamic morphology,structural form and composite layer,and the corresponding optimization model is established.Through the comparative analysis of the optimization results,the feasibility and effectiveness of the proposed method are proved.The main research work is as follows:(1)In order to improve the aerodynamic performance of the blade,a method for optimizing the aerodynamic performance of the blade based on quantum genetic algorithm is proposed.The chord and the twist of the blade described by the Bezier curve are used as design variables,and the blade shape optimization model with the maximum blade power as the optimization goal is established.Compared with the optimization results of the classical genetic algorithm,the aerodynamic performance of the blade optimized by the quantum genetic algorithm is better under the same parameters and boundary conditions,and the blade power is significantly improved.(2)In order to improve the structural efficiency and structural performance of the blade,the topology optimization method is applied to optimize the design of the blade support structure.Select the blade web structure as the design area.To establish a topology optimization model with the objective of minimizing blade flexibility.The weight reduction of the topology structure obtained is obvious.At the same time,redesign based on topology optimization results.The influence of redesign on topology optimization results under different parameters is analyzed to verify the feasibility of redesign structure.(3)Aiming at the problem that the maximum stress concentration of the wind turbine blade is distributed in the area near the blade root and causing the blade fatigue damage,the finite element method and the NSGA-II algorithm are combined to optimize the composite blade layup.Taking the ply thickness as design variables,a multi-objective optimization model with the lightest blade weight and the smallest maximum stress as the optimization objectives is established.The Pareto optimal solution set is obtained by iterative solution.The optimized blade has obvious weight loss and the maximum stress is significantly reduced,which saves the material cost and increases the reliability of the blade.