An experimental test of the performance enhancement of a Savonius turbine by modifying the inner surface of a blade

Abstract The Exploiting wind energy in the areas available to it to generate electric energy, which is a type of renewable energy. The Savonius turbine could be a type of vertical axis wind turbine of choice for power production and off-grid application, allowing exploitation in confined spaces and areas with low wind speed. This research aims to improve the performance efficiency of Savonius elliptical turbines by developing parameters of blade shape and overlap ratio. A series of 2D unsteady simulations (CFD-Fluent version 19.1) with using k-ω SST (Shear-stress transport) model of the classical Savonius elliptical turbine (Model-2) was performed by improving the overlap ratio of the rotor. Classical elliptical Savonius turbine was modified by changing the overlap ratio from the value (0.1, 0.15, and 0.2). Then, modifying the inner surface of the blade in the concave part and it into a regular zigzag shape (Model-1), and testing the models in an open wind tunnel system. As the result of the 2D simulation of Model-2 at OR = 0.2 the increase value of the obtained maximum power coefficient is 3% and 5.54% compared to the overlap ratio (0.15 and 0.1), respectively. The result of the experimental test was obtained the maximum power coefficient (0.292, 0.26) at wind velocity (9 m/s), for modified model and classical model respectively. Here, the Model-1 gave the best contribution in raising the performance efficiency of the elliptical Savonius turbine.