High Efficiency Energy Harvesting Using a Savonius Turbine With Multicurve and Auxiliary Blade

A new blade configuration is proposed to further increase the performance of a Savonius rotor through a sequence of unsteady two-dimensional (2D) computational fluid dynamics (CFD) simulations. The blade is made by a multicurve and auxiliary profiles for a reduction of the negative drag on the rotor. The flow aspects around the new blade are analyzed and quantitatively compared with that of the conventional and other blade configurations. The results imply a dependency of the rotor performance on the blade shape, demonstrating an appropriate configuration that produces the highest coefficient of torque and power. The newly optimized configuration is recognized with the peak of power coefficient at a tip speed ratio (TSR) of 1.5, which is more than two times higher than the conventional one. This makes the Savonius rotor better applicable to the urban environment. Importantly, this blade significantly increases the power coefficient by 6.3% at TSR < 1.0, known as a typical working condition in rural areas. The present results thus point out a feasible solution for powering the poor-households with no access to the grid and reducing the harmfulness to the environment, with high efficiency in wide operating conditions over the previous designs.