Design of a 5kW horizontal axis wind turbine using experimental and numerical methods

In this paper, the S805 airfoil is chosen as the basic section for the design of a 5kW horizontal axis wind turbine (HAWT). At the beginning, both physical and numerical models of the S805 airfoil were constructed and the experimental measurements of the lift and drag coefficients have validated the results obtained by the two dimensional (2D) computational fluid dynamics (CFD) under the Reynolds number (Re) of 1.25×10⁵ and 2.5×10⁵. The Blade Element Momentum method (BEM) is consequently used to design the blade geometry of the wind turbine based on the experimental results of the airfoil. A 3D CFD model is constructed to test the designed wind turbine obtained. It is found that the power coefficient of 0.38 determined by the 3D CFD model is higher than 0.34 obtained by the BEM method. The difference should be due to the stall delay in the rotation flow field of the wind turbine model, which was confirmed by the simulation results that the flow remain attached to the blade surface when wind velocity has reached 20m/s. The behaviors of flow separation were also investigated under different wind speed in order to improve the performance of the designed wind turbine blade.