Research Of Large Wind Turbine Blade Design Optimization In Low Wind Speed Based On Genetic Algorithm

China is a country with vast territory and its wind energy resource is significantly rich. But with the rapid development of large-scale wind power industry, the exploitation of wind energy resource in higher wind speed on land is close to saturation, and the use of technology is rounded to mature. Actually the wind energy resources of our country in low wind speed are richer and widely distribution, occupying about 70% of the whole country’s wind energy resources and having huge development value. Therefore the exploitation scale of wind power project applicable to four wind resource area(including weak three wind resource area) is gradually expanding; the needs of low speed wind turbine have increased dramatically. The kernel of exploitation of low-wind-speed wind power lies in the energy capture efficiency of wind turbine blade, so the merits of the wind turbine are determined by the blade’s design quality, and the blade is composed of a series of airfoils according to certain rules, so study on low speed wind turbine such as the selection of wind turbine blade airfoils and blade aerodynamic performance optimization design play a key role to improve the wind energy conversion efficiency of low speed wind turbine and reduce the unit cost. Sponsored by the National Natural Science Foundation of China “Megawatt wind power generator dynamic characteristics research and life prediction of the blade”(NSFC: 51065026) and the Autonomous Region Natural Science Foundation “Megawatt wind turbine blade state of degradation and failure mechanism research”(ARNSF: 2011211A002), this research is mainly focused on the large low speed wind turbine blade shape optimization design method, theory and key technology. The main contents are as follows,First of all, the Betz theory suggests that the biggest wind energy utilization coefficient of wind turbine is 0.593 and there is no kind of wind turbine’s maximum wind energy utilization coefficient can exceed this limit value. After analyzing wind turbine design theory,I think that to determine the design parameters of wind turbine blade and loads is still based on the blade- momentum theory. Aiming at the low wind speed area namely wind energy available area, I trying to take the modified strip theory model as the design method, then the design parameters of low speed wind turbine blade such as the starting wind speed, rated wind speed, rated power, tip speed ratio and rotor diameter are determined. By this time the choice of basic design parameters of low speed wind turbine blade is completed.And then this paper introduces basic concepts associated with airfoils, traditional series airfoils and special wind turbine airfoils. CFD software FLUENT is used to do the aerodynamics performance analysis including pressure field, velocity field and lift-to-drag ratio of three kinds of S series airfoil S816, S817 and S818,verifying the aerodynamic performance of the three airfoils. Then leaves these airfoils to make solid modeling and performance validation, and the results meet the requirements of design task.Finally, taking the maximum coefficient of lift-drag ratio as the optimization goal, the blade chord length and twist angle as optimum design variables, and then the mathematical model of wind turbine blade shape is established. Based on the theory of genetic algorithm and using this optimized model to do optimization design research for the designed 2MW wind turbine blade. Results show that the optimized blade has better aerodynamic properties.