Numerical investigation of wind-lens combinations for improving aerodynamic performance of an elliptical-bladed Savonius wind turbine

Savonius turbines have potential for diverse applications. Despite their relatively low efficiency, the aerodynamic performance of Savonius rotors can be enhanced. This investigation seeks to examine the impact of different wind-lens combinations on the aerodynamic performance of a two-dimensional elliptical-bladed Savonius rotor. The study accomplished independence from both mesh elements and time-step size, and numerical results were juxtaposed against relevant experimental data. Four wind-lens configurations were tested, namely, diffuser (S1), nozzle diffuser (S2), diffuser brim (S3), and nozzle diffuser brim (S4), with a notable decrease in the power coefficient being observed at all tip speed ratios. Subsequently, modifications were made to these models for the Savonius rotor (S-M1, S-M2, S-M3, and S-M4) via changes to their positions and angles, resulting in significant improvements to the aerodynamic performance of the elliptical-bladed Savonius rotor. The maximum power coefficient was observed to be 0.227 at a tip speed ratio of 1.0 for the elliptical-bladed design, whereas the S-M4 model exhibited a maximum power coefficient of 0.404 at the same tip speed ratio.