Aerodynamic performance of NACA four-digit profiles in small-scale wind turbines for small farms

In Brazil, there are many places that do not have access to electric energy, mainly in rural areas with small farms. This situation has accentuated the importance of renewable energy sources, such as wind energy. This work consisted of the design, construction and field testing of two small three-bladed wind turbines with two different aerodynamic profiles. The aim of the study was to compare the profile influence on the turbine aerodynamic performance. Using the blade element momentum (BEM) theory, two wind turbines were designed and built with different cross-section aerodynamic profiles (NACA 0012 (symmetric) and 4412 (chambered)). Following statistical analysis, the results of the field tests demonstrated that the performances of the turbines are similar when the rotational speed is near the designed value (lambda = 5). However, when the rotational speed is under or above the designed value, the NACA 4412 profile yields superior performance.