The Optimal Design Of Horizontal-Axis Wind Turbine Blade

Facing imminent energy and environmental crisis, and wind development costs continue to reduce,countries were to further increase efforts to develop wind power .Wind turbine is the core of wind energy,and horizontal-axis wind turbine is the most common form of wind turbines. The blade is a key component of horizontal axis wind turbine, the shape of it decided the wind energy conversion efficiency, thus the optimal design of blade is the primary task of the wind machine design. In addition, the dynamic characteristics of the blades had an important effect on their deformation and life. Therefore, to study it is also very necessary.In this paper, the horizontal axis wind blade aerodynamic shape optimization and dynamic characteristics were researched. The main work and conclusions of the paper were as follows:①The domestic and international development status of horizontal axis wind turbine and the blade design wind turbines were stated. The blade aerodynamic optimization of horizontal axis wind turbine was reviewed.②The horizontal-axis wind turbine aerodynamic theory and Wilson method were introduced in detail.③Considering the cascade theory, tip losses, root losses, blades 3-d rotating effect, stall correction of momentum theory and other modifying factors, the aerodynamic performance calculation model was established on the basis of strip theory. NREL 20kW wind turbine aerodynamic performance was calculated according to this model, contrasting the results of NREL, which showed the model was correct and practicality.④Fixed-pitch and pitch-variable wind turbines were designed using two different methods in this paper. For fixed-pitch wind turbines blade optimization,the design attack angles was treated as a variable, considering the blade airfoil section aerodynamic characteristics, the constraints between the blade section and the wind speed probability distribution of wind farm, an optimization model with the objective of maximum annual energy production is established in the range of rated power and basic operating wind speed. The blade geometry of a 20kW fixed-pitch wind turbine was optimized using genetic algorithm according to the model. Through the evaluation of the aerodynamic performance of 20kW fixed-pitch wind turbine and the comparison with the same type wind turbine of NREL, the results showed that optimized wind turbine has a better aerodynamic performance. For pitch-variable wind turbines blade optimization, using first Wilson theory to design of blades preliminary, and then treating the design attack angles as a variable, using genetic algorithm to design again. Through the blade optimization and the aerodynamic performance evaluation of a 1.0MW pitch-variable wind turbine, the results showed that optimized wind turbine had a better aerodynamic performance, which illustrated the superiority of this design method.⑤The two-dimensional airfoil profile data points were converted into three-dimensional data points of blades through a complex matrix of coordinate transformation. And a solid modeling of blades was established by three-dimensional modeling software UG, which provided some new ideas for establishing distortion modeling and other complex solid modeling.⑥The finite element model of the blade was established through three-dimensional model, and the blade vibration modal and the Campbell diagram were analyzed by ANSYS Workbench. The results showed that the main vibration form of blade were waved and shimmy vibration, the resonance phenomenon did not occur when blades running at rated speed.