| Wind turbine blade is an important part of a wind turbine to absorb wind energy, its aerodynamic performance determines the wind turbine’s utilization efficiency. In wind turbine blade design, the airfoil chord length, torsion angle and the exhibition of airfoils decides the aerodynamic performance of wind turbine blade that is where the focus of the research works. Design of wind turbine blade’s aerodynamic characteristics can generally be divided into two kinds of schemes, one scheme design obtain parameters such as chord length, torsion angle using iterative method based on the aerodynamic design principle, then according to restriction of the chord length, torsion angle curve, the chord length in the practical engineering, torsion Angle curve type; Another is combining with optimization theory to achieve chord, twist angle curve parameters by seeking wind turbine a performance(such as wind energy resource utilization, energy output) optimization to continuously optimize chord, twist angle curve. However, no matter what the program is over, the researchers tend to position the main wing fixed in advance, and then performs the blade aerodynamic design. And this may cause the design of wind turbine blades aerodynamic performance will not be optimal.On the use of genetic algorithms, the position of the chord length, twist angle and the main airfoils distributions as variables, quadratic uniform B-spline curve to control the chord length, twist angle curve, in order to maximize the utilization factor of wind energy resources objectives, to make wind turbine blade design to optimize aerodynamic performance studies.Main work is as follows:(1) The establishment of a different thickness for different positions of the wind turbine airfoil database, including database under different Reynolds numbers each airfoil aerodynamic parameters, in order to facilitate the call of the wind turbine blade aerodynamic design.(2) Based on the classic wind turbine blade aerodynamic theory, the authors consider blade loss(loss tip, blade root loss), thrust amended leaf thickness and width of the blade element changes the angle of attack, the author iterative induction factor and Reynolds number, and prepared a wind turbine aerodynamic performance calculation program.(3) Using multi-wing arrangement design method, tip portion disposed NERL S832, the leaf portion disposed NERL S831 and S830 airfoil blade root portion disposed NERL S818 airfoil, using the approach of thickness’ s linear averaging to deal with the transition airfoil.(4) Using uniform quadratic B-spline curve to control the chord length and torsion Angle curve, it is better than the Bezier more flexibility, and has the ability of local modifications.(5) Using the wind turbine blade aerodynamic performance calculation program as the basis of individual evaluation, through study of wind turbine blade optimization design, the author found a wind turbine blade that wind energy utilization coefficient is 0.4807, and draw out the performance parameters curve of the wind turbine.(6) Author calculates the steady-state performance of variable speed-constant frequency wind turbine, draw out the curve of wind turbine output power, rotating speed, pitch angle,atc.The wind turbine blade aerodynamic optimization design method adopted can be used as a reference method in wind turbine blade design. |
