Research On New Wind Turbine Airfoils And Their Aerodynamic Performances

The new wind turbine airfoils and their aerodynamic performances are presented in this thesis. The study is supported by the NSFC project 揜esearch on the Development of New Airfoil Series for Wind Turbine and their Aerodynamic Characteristic Analysis? for the study of the aerodynamic performances of the new wind turbine airfoils, both the theoretical calculation and the wind tunnel test were used. In the thesis, three sections are mainly included: theory of wind turbine airfoils, aerodynamic performance prediction and wind tunnel test and analysis. In the first part, some basic concepts regarding airfoil and airfoil flow were introduced, the Reynolds number, Mach number and boundary layer were typically explained. fhe geometric parameters, aerodynamic characteristics of airfoils and their effects on airfoil aerodynamic performances were discussed. The geometric parameters, which include chord, leading edge radius, thickness, camber line, camber and trailing edge radius, have a direct effect on airfoil aerodynamic performances. The aerodynamic characteristics of airfoils include Reynolds number, boundary layer, roughness, turbulence and angle of attack, etc. Meanwhile, the characteristic and aerodynamic performance of the typical traditional wind turbine airfoils and the new wind turbine airfoils, and their applications in wind turbine design were emphatically discussed. In the second part, an interactive viscous/inviscid approach was used to predict the aerodynamic performances of the airfoils, and the prediction model was also discussed in detail. The aerodynamic performances of two typical wind turbine airfoils with different Reynolds number and Mach number was predicted using the software XFOIL, which is a kind of analysis and design software for low Reynolds number airfoil. The analytical results showed that Reynolds number and Mach number have a rather obvious effect on airfoil aerodynamic performances. The bigger the Reynolds number, the higher the lift coefficient of airfoil; the bigger the Mach II Abstract number, the lower the lift coefficient and the higher the drag coefficient. Moreover, the direct numerical optimum design of the airfoil shape using XFOJL was also investigated. The design variables are leading edge radius, camber of the camber line and trailing edge radius, and the objective function of the design is the weighted sum of max lift coefficient and lift/drag ratio. A new airfoil which has the same relative thickness, similar profile and better lift and lift-drag ratio compared with the referenced airfoil was gained. The wind tunnel test was conducted at the Wind Tunnel Laboratory in Shantou University. The aerodynamic performances of two FFA-W3 airfoils at wind speed of 8m/s and 12m/s were gained, respectively. The range of angle of attack of one of the two airfoils is from ?300 to 420, and the other is from ~300 to 600 . The comparisons of the perfonnances between the test and calculation were shown in good agreement. It is demonstrated that the calculation method applied was effective in the performance prediction.