Otimização geométrica do rotor Wells aplicado em usinas de coluna de água oscilante

Abstract

rotor with 8 blades formed by NACA 0015 airfoils of constant chord length is carried out. The results obtained for the turbine performance characteristics (torque coefficient, total pressure drop coefficient across the turbine and efficiency) are compared to experimental and numerical values available in the literature. In order to carry out the numerical simulations of steady state flow in the Wells turbine rotor, a periodic hydraulic channel and a single computational domain were used. An unstructured mesh was employed, with prismatic layers close to the rotor blade surface. The k-ε Realizable turbulence model was used with improved wall treatment. For the pressurevelocity coupling, the SIMPLEC method and second-order discretization and interpolation schemes were used. In a second approach, an optimization methodology for maximizing the torque coefficient and the rotor efficiency of the Wells turbine is presented. The optimization process consisted of generating a DOE (Design of Experiments) experiment plan, where the profiles chord length and blade thickness were defined as geometric design variables, both parameterized and referring to the average height and tip of the blade. After carrying out numerical simulations of the flow at all points of the DOE, a statistical analysis was applied to the results obtained, verifying that the thickness of the blade does not statistically have a significant influence on the aerodynamic performance of the Wells turbine rotor. The results obtained provided two optimal geometries for the Wells turbine rotor, the first geometry (Optimized A) presented a maximum gain of 31.11% for the torque coefficient and 13.59% for maximum efficiency. The second geometry (Optimized B) showed a gain of 20.18% for maximum efficiency and a reduction of 5.44% for maximum torque coefficient.