Enhancing aerodynamic efficiency: shape modification of airfoils
Hossein Seifi Davari, Ruxandra Mihaela Botez, Mohsen Seify Davari, Harun Chowdhury
Abstract
Small wind turbines (SWTs) are essential for harnessing renewable energy, particularly in developing regions where energy demands are significant. They provide a sustainable solution to meet the critical energy needs of these areas. However, the low Reynolds number (Re) airflow characteristics can pose challenges, making optimising airfoil shapes essential for enhancing aerodynamic performance and energy capture. This study offers a thorough analysis of six different airfoil profiles within a Re range of 50k to 500k. Modifications to the thickness-to-camber ratio (t/c) were strategically targeted to improve aerodynamic efficiency and structural viability. Using QBLADE software, we evaluated these design alterations to optimise the lift coefficient (CL), drag coefficient (CD), stall angle of attack (αstall) and lift-to-drag coefficient ratio (L/D). The analysis revealed significant improvements in the maximum power coefficient (Cp.max), with the modified BW-3 airfoil achieving a Cp.max of 0.441 at a Re of 500k – a remarkable 40.5% increase over baseline values. This consistent enhancement across various Re emphasises the essential impact of aerodynamic design in enhancing energy capture and reinforcing the feasibility of SWT applications across diverse operating conditions, along with material savings that lead to lighter wind turbine (WT) blades.