Abstract
Among the existing wind energy harvesters, the vertical-axis Savonius wind turbine rotor is found to be suitable for small-scale power generation. It is a drag-driven device where the pressure of the fluid stagnating within its blades results in its rotation. The high starting torque and poor operational efficiency of this type of turbine rotor are its distinguishing features. The main geometric and flow parameters that influence its performance are its blade profile, overlap ratio, aspect ratio and Reynolds number (Re). Among these parameters, the blade profile influences significantly on the power production. Recent studies have shown that, choice of an elliptic blade can help in harnessing more wind energy, however, it is desirable to characterize this choice through detailed studies. The present study aims at evaluating the performance of a two-elliptical-bladed Savonius turbine rotor for its dynamic torque and power characteristics. In order to characterize its performances, the developed rotor is experimented in an open circuit low speed wind tunnel. The experiments have been carried out at different Re values so as to estimate the dependence of rotor performance on Re. When the Re is increased from 57310 to 164766, the maximum power coefficient (CPmax) of the turbine rotor has shown an improvement of 43%.
