Optimal Design and Analysis of a Mixed Airfoil Blade for Small-Scale HAWTs
Geneti Temesgen Terefa, Jackson G. Njiri, Patrick Muiruri, Chala Merga Abdissa
Abstract
This study investigates the optimum aerodynamic performance of small-scale Horizontal Axis Wind Turbines (HAWTs) utilizing a mixed-airfoil blade design. The QBlade software was employed for the selection of the best performing airfoils based on the lift-to-drag ratio and a range of operational performance. Additionally, the Blade Element Momentum (BEM) theory was deployed for the analysis of the blade's design and performance. Finally, in Computational Fluid Dynamics (CFD), the SST k-ω turbulent model was also applied for better analysis. The key findings demonstrated that the optimal airfoils including SG6040 (root), NACA 4711 (middle), and SG6043 (tip), were chosen based on their superior lift-to-drag ratio and structural integrity. Furthermore, the designed mixed-airfoil blade achieved power coefficients of 0.454 (BEM), 0.432 (QBlade), and 0.395 (CFD) at a Tip Speed Ratio (TSR) of 5.5, which are greater than the conventional single-airfoil designs. It was concluded that mixed-airfoil configurations significantly enhance the aerodynamic efficiency of small scale wind turbines, and that future research on structural analysis and torque control mechanism integration is essential to further optimize performance and energy capture.