Estudos de formas de aerofólios para turbinas eólicas de pequeno porte

Abstract

This work presents an aerodynamic study of airfoils applicable to small wind turbines, focusing on the E423 and S809 profiles. The analysis was carried out through Computational Fluid Dynamics simulations, using FreeCAD and cfMesh for the construction of the computational domain and mesh generation, OpenFOAM for the numerical solution, and ParaView for post-processing, all of them are free, open-source software packages. Furthermore, they are used together within a unified platform called CfdOF, which is integrated into FreeCAD. Initially, the methodology was validated with the E423 airfoil at a Reynolds number of 300.000, comparing the aerodynamic coefficients obtained with numerical and experimental data available in the literature. The mesh refinement study indicated that the mesh with a characteristic size of 4.0 mm presented better agreement with the reference data. Using this mesh, angles of attack of 0°, 4°, 8°, and 12° were simulated, showing an increase in the lift coefficient with angle of attack and a more pronounced drag increase at 12°. The comparison an average deviation of approximately 1.93% for the lift coefficient, indicating good agreement between the numerical and experimental results. After validation, the methodology was applied to the S809 airfoil, developed for wind turbine applications, allowing a qualitative analysis of pressure and velocity fields. The results indicate that the adopted methodology is suitable for preliminary analyses of airfoils applied to small wind turbines.