Hello everyone, I am working on the aerodynamics of blades of a Horizontal axis wind turbine .I want to know how to pick the best airfoils along the blade studied . for example if I have a 100 kw wind turbine and i would like to mixt 4 different airfoils in my blade , how do i know the type of those airfoils , and thier orde along the blade ?
the proven blade for HAWT is the Cretin sail...forget about mixing different type of aerofoils it lead to vibration problems...well if insist on selecting the aerofoils then refer I,R, Abbot and Von Doenhoff book Theory of Wing Sections ..good luck
There are number of factors that can be considered before selecting an airfoil for wind turbine blade such as, aerodynamic performance (cl/cd), structural rigidity (maximum thickness), roughness sensitivity, acoustic performance, dynamic stall behavior etc. However, if given a choice of airfoils for wind turbine blade, with a simplest approach, one can make decision based on aerodynamic performance and structural rigidity.
Generally, in a wind turbine blade, the blade sections near the hub/root have relatively little contribution to the overall aerodynamic performance of the blade but bear significantly high structural loads of the blade. Thus, it is generally preferred to have thick airfoils for the blade sections near the hub/root of the blade, since thick airfoils are known to have better structural performance at the cost of aerodynamic performance.
Whereas, as the tip of the blade is approached, the blade sections near the tip contribute the most to the overall aerodynamic performance of the blade but have less structural demands. Hence, thin airfoils, which offer better aerodynamic performance at the cost of structural performance, can be utilized for the blade section near the tip.
Neeraj Verma thank you for your answer. then I guess every time I have to choose the airfoils of blades sections of an X kw wind turbine i have to made a comparison between the various airfoils that exist in the litterature to obtain the optimal ones? an there is no way to know exactly which airfoil is the best for my HAWT ?
There are many airfoil families dedicated for wind turbines like NREL S airfoil or DU airfoil. The profile should be selected according to its max. Cl/CD value and its thickness to chord ratio. There are some other criteria, but as far as I know these two are the main criteria.
For Cl/CD ratio, this should be as high as possible to give the best performance. For thickness to chord ratio, the should be selected according to the structural analysis and optimization of the blade design to give a tip deflection that compiles to the IEC standards.
Jinane Radi , There are some recommended options of airfoils for wind turbine blades of different categories (rated power). One can work around these recommended families of airfoils. If you’re designing a new airfoil for a given category of wind turbine, comparing the performance of your designed airfoil with the recommended set of airfoils for the corresponding category of the wind turbine will also work most of the time. You may refer to the following paper for the recommended set of airfoils. Other recommended airfoils can also be found in the literature.
Khaled Yassin thank you Mr.khaled for all the information you have shared with us
Neeraj Verma yes i get the idea
thank you for sharing this informations
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