The focus of the present study is to examine the performance of the conventional and modified Savonius turbine with and without deflectors. First, the performance of the conventional Savonius rotor and a modified Savonius rotor, which originally proposed by Bach [7], were examined through both experiments and numerical simulations. The numerical study, which employed the computational fluid dynamics
software, STAR-CD, aimed to provide detailed analysis of the factor affecting rotor's performance with both 2-D and 3-D simulations. The numerical results of the convention Savonius rotor were also compared with the experimental study presented by Blackwell et al. [2], with favorable results. Both experiments and simulations have shown better performance of the modified Savonius rotor with the improvement of efficiency being about 3% to 5 %. Second, the deflector configurations, which reported by Altan et al. [10] and Kailash et al. [12], were added around the conventional Savonius rotor in numerical simulations to examine their effects on the rotor's performance. With the addition of the deflectors, it has been revealed that the maximum power output from the rotors can significantly increase by 40%.

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