This project belongs to the field of power engineering and new energy utilization. Wind energy is the renewable energy with the most large-scale development and utilization value and prospects. It is highly valued and developing rapidly around the world. China has the world's largest wind power market and urgent development needs. Wind turbines convert wind energy into mechanical energy through impellers to drive generators to generate electricity. Their flow control and efficiency enhancement methods are the core key technologies of wind turbines, which determine the performance and product competitiveness of wind turbines. With the support of the National Natural Science Foundation of China, the 863 Plan, the Shanghai City Outstanding Subject Leaders Program, international cooperation and enterprise industry-university-research and other projects, with the goal of improving the wind energy conversion efficiency and stable operation of wind turbines, the development requirements of large-scale, flexible and offshore wind turbines, wind turbines are always operating in unstable natural environment conditions, and the lack of independent research and development and design methods for wind turbines in China. After more than ten years of efforts, key issues such as impeller aerodynamic structure design, A number of key technologies have been broken through in blade complex flow control, efficient and stable operation of large wind turbines, etc., and the following original achievements have been achieved: 1. A curved swept blade and a blade structure with a blade tip winglet are invented, which can improve the wind energy conversion efficiency by 1%-6%. A load reduction method for a non-straight blade with a thick trailing edge structure to self-adapt deformation according to the incoming flow condition is proposed, and a low fatigue load super-large flexible blade with rigid-flexible coupling characteristics is successfully developed, which can reduce the wind wheel load by 3%-15%. 2. The aerodynamic design method of wind turbine under off-rated condition is established, and the operating efficiency of wind turbine under all working conditions is improved. A new method for calculating wind turbine energy conversion is proposed, which solves the problem of low accuracy of wind turbine aerodynamic performance design methods in the near and post-stall regions. A DU-SELIG static stall model is established to solve the problem of inaccurate wind turbine efficiency design caused by stall delay effect under high wind speed conditions, which can increase wind energy conversion efficiency by 5-10%; A dynamic stall model has been established to solve the problem of inaccurate wind turbine efficiency design under unstable conditions, and can increase wind energy conversion efficiency by 2-5%. 3. A new method for flow control of wind turbines has been invented, which ensures the operating efficiency and stability of wind turbines in complex and changeable environments. Through innovative measurement methods, complex flow information of wind turbines is quantitatively determined, and the problem of refined control of blade flow is solved; a blade flow reorganization method using a slight front winglet of the deflector is proposed, which solves the problem of low work capacity and high fatigue load in the middle and rear sections of wind turbines; reveals the aerodynamic-hydrodynamic multi-body dynamic coupling law of offshore floating wind turbines, and solves the problem of stable and safe operation of large offshore floating wind turbines to a certain extent. The project has received 14 nationally authorized invention patents and 58 SCI/EI papers, which he cited 1351 times. A group of R & D teams in the field of wind power generation have been cultivated, and the research results have also been applied in other fields of turbomachinery. The above-mentioned series of new technologies for flow control and performance improvement of wind turbines formed by the project are the first international effective methods proven by practice. They have enhanced my country's ability to independently develop internationally advanced wind turbines and promoted the technological progress of the wind power industry and the competitiveness of products in the international market. The results of the project have been applied in the development of wind turbines by Shanghai Electric, China Datang, Mingyang Wind Power and other enterprises. In the past three years, nearly 1500 sets of large megawatt wind turbines have been newly developed and modified, resulting in an output value of 2.1 billion yuan and a profit of 250 million yuan. Among them, the SCD76.6 blade unit developed in cooperation with Mingyang Smart Energy has the best power generation efficiency in the Xinghua Bay Offshore Experimental Wind Farm, and ranks first in the world in offshore wind power orders; the S66 blade developed in cooperation with Shanghai Electric has been realized for the first time in China. Self-designed blades have been licensed to other blade factories for production, breaking the situation that blade license production has always been monopolized by foreign countries.