A new 360° airfoil model for predicting airfoil thrust potential in vertical-axis wind turbine designs

Abstract

Vertical-axis wind turbine (VAWT) configurations expose the airfoil sections of turbine blades to angles of attack between 0° and 360°. In designing new VAWT configurations or improving existing configurations, some knowledge of the aerodynamic forces at these angles must be known. This paper presents a model for predicting 360° of aerodynamic forces acting on the s1210 airfoil at two low Reynolds-number conditions. This model is based upon results from wind-tunnel experimentation and achieves a close approximation of the measured performance of the airfoil. Models such as this provide the means to predict airfoil lift and drag characteristics and use those results to predict the thrust capabilities of the airfoil as the turbine blades rotate. The model is presented and compared with other post-stall models within the literature. These comparisons show that this model is superior to previous models when applied to the s1210. The model shows that two angles of attack regions between 0 and 30° and then again those between 180° and 300° provide the highest thrust contributions of the airfoil. Using models such as these for system-level analysis provides the means to assess the feasibility of different VAWT configurations. Furthermore, it provides the means to assess the proper spacing and distance between turbine blades to generate the desired thrust. This enables the designer to determine the optimum turbine geometry in order to maximize performance.