Optimizing design parameters for slotted blade Savonius hydrokinetic turbine: A multi-fidelity approach

This study significantly improves the performance of slotted Savonius hydrokinetic turbine (SHT) by identifying an optimal configuration through a systematic investigation. This analysis, utilizing 2D CFD simulations coupled with Taguchi's method, reveals that a two-bladed Benesh profile with a 0.1 overlap ratio is the optimal design. This configuration achieves a remarkable 90.98% improvement over the baseline semi-circular SHT, reaching a maximum power coefficient (C_P​) of 0.3537 at a TSR = 0.9. The Taguchi analysis demonstrates that the number of blades is the most critical factor influencing turbine performance, followed by blade shape, overlap ratio, and tip speed ratio. Notably, the slotted Benesh profile outperforms other slotted designs, while the airfoil profile excels among SHT designs without a slot. To validate the findings, 3D simulations are conducted on the Taguchi-optimized slotted SHT, showing a 9.52% reduction in maximum C_P ​compared to the 2D results. Crucially, subsequent experimental investigations show strong agreement, with only a 4.23% deviation from the 3D simulation results. In conclusion, this research unequivocally demonstrates that incorporating a slot enhances SHT performance for the profiles studied, offering key insights for future designs.