Influence of Tip Speed Ratio on the efficiency of Savonius wind turbine with deformable blades

Abstract

Improving machines efficiency and searching for their new applications are the main topics in the development of the renewable energy industry. In the case of Savonius type wind turbines, the works aim at the improvement of aerodynamic performance. The CFD simulations of a turbine equipped with deformable blades showed a significant positive impact of this enhancement on the machine aerodynamic efficiency. Previously, the investigation was carried out for a TSR (Tip Speed Ratio) equal to 0.8, typically recognized as the point of maximal efficiency for conventional Savonius wind turbines with rigid blades. However, the continuously altering shape of blades during their rotation can influence the optimal TSR. Therefore, the efficiency of the deformable blade turbine was investigated in a wide range of TSR. In this paper, the previously developed quasi-2D model with a two-way Fluid-Structure Interaction method was employed to obtain turbine efficiency characteristics as a function of TSR. The maximum power coefficient Cp was achieved at TSR = 0.9. Obtained characteristic was compared with data for a conventional rigid blades turbine, gathered with a comparable sliding mesh model.