Experimental and numerical studies for optimization of modified Savonius hydrokinetic turbine system

As global efforts to mitigate climate change intensify, hydrokinetic turbines play a crucial role in advancing sustainable energy solutions. This study enhances the coefficient of performance (Cp) of a modified Savonius hydrokinetic turbine through a novel compound asymmetric deflector configuration comprising a dual-plate upstream and a single downstream deflector. Experimental investigations were conducted in an open-channel flume, revealing increased flow velocity and improved turbine response. The results were numerically validated using ANSYS CFX 2022 R1, followed by multi-parameter optimization via screening and the multi-objective genetic algorithm (MOGA) to determine the optimal deflector lengths, positions, and angular orientations. The deviation between the experimental and numerical results was 5.77%. The optimal upstream and downstream deflector placements were found to be 1.46D and 1.64D, respectively, with angular positions of 98.55° and 127.27° and lengths of 0.70D and 0.36D, respectively. Experimental validation of the optimized configuration demonstrated a 2.83% improvement in turbine performance, confirming the efficacy of the proposed deflector arrangement. The study establishes a comprehensive framework that unifies experimental testing, numerical modeling, and optimization, providing a simplified yet efficient approach for enhancing Savonius turbine performance in low-velocity hydrokinetic environments.