A NUMERICAL STUDY ON COMBINED EFFECT OF DEFLECTOR PLATE, TWIST ANGLE OF BLADES, AND TIP SPEED RATIO ON THE PERFORMANCE OF SAVONIUS HYDROKINETIC TURBINE

Abstract

Savonius Hydrokinetic Turbine (SHT) is a small-scale renewable energy source that is a sustainable solution for remote areas and rural electrification. The current research work establishes a numerical study on combined effect of deflector plate (no deflector, deflector at 90°, deflector at 45°), twist angle of blades (0°, 12.5°, 25°), and tip speed ratio (0.5 to 1.5) on the turbine efficiency in terms of power coefficient (Cp) using CFD simulation considering a realizable k-ε turbulence model. A total of 99 simulations were performed considering all the above different conditions. To validate the results, simulations were compared with the results of a previous study having no deflector plate. It has been identified that SHT with blade twist angle of 12.5° and deflector plate at 90° produces highest power coefficient as 0.364 at tip speed ratio of 0.9 and 0.5 m/s water velocity. Similarly, SHT having a blade twist angle of 25° with deflector plate at 90° yields the highest torque coefficient as 0.454 at a TSR of 0.5. It was observed that Cp increases by an average 15% for SHT having blade twist and deflector plate as compared to SHT without blade twist and deflector plate.