Levantamento da curva de desempenho de aerogeradores de pequeno porte projetados com perfis naca de quatro dígitos, através de simulação númerica utilizando a Biblioteca de CFD OpenFOAM

Abstract

This work consisted in using the open source library of Computational Fluid Dynamics (CFD) OpenFOAM, to obtain the solution for a steady three-dimensional flow on small wind turbines, applying the RANS turbulence models k-ε and k-ω SST. Aiming to estimate the theoretical efficiency curve, values were calculated for the power coefficient at different tip speed ratios. The rotor has a diameter of 1.5 m and consists of three blades designed by the Blade Element Momentum (BEM) method for the tip speed ratio equal to five and using NACA four-digit profiles (4412 and 6412). The simulations were performed assuming a free-flow speed equal to 7.5 m/s. For each of the situations described was carried out a set of 6 simulations, in which the blade speed of rotation was varied according to the desired tip speed ratio - 2, 3, 4, 5, 6 and 7. The pressure and viscosity momentum on the blades obtained in each of the simulations were used to calculate the power coefficients. The results showed that the models used provide higher power coefficients for profiles with small camber, as NACA 4412 and it is compatible with the literature data.