Análise hidrodinâmica de diferentes geometrias de pás na performance de uma turbina hidrocinética via DFC

Abstract

Hydrokinetic turbines are devices that generate electrical energy by converting the kinetic energy of bodies of water, such as rivers and ocean currents. As with wind turbines, their performance is influenced by aerodynamic phenomena, such as vorticity and turbulence. In that way, this study aims to analyze the impact of modifying the blade geometry of a hydrokinetic turbine on the mitigation of these phenomena and the increase in extracted power. For this purpose, a hydrokinetic turbine previously developed by Funatsu was selected, having been optimized, modelated and numerically simulated using Computational Fluid Dynamics (CFD). Compared to the results presented by Funatsu, a lower value of extracted power was observed, as a consequence of the vorticity and the flow turbulence, which are elements that are not taken in account in the analytical calculations. Willing to decrease the incidence of vortices, the modeled turbine was modified, resulting in four rotors with different distances between the blades, two rotors with blades angled relative to esch other and two new toroidal rotors, similar to the toroidal propellers developed by MIT, which were simulated in CFD under the same conditions as the first rotor. About the power, the extracted values from both rotors were lower than that of the first simulated rotor, with differences of 52,6% and 6%, respectively. However, in terms of vorticity, joining the blade tips caused a decrease in the vortex generation. As the toroidal propelers purpouse is to decrease wing-tip vortex formation, it can be seen that this goal was achieved, even though it reduced the power generation.