Experimental and CFD Analyses of Two Bladed Savonius Water Turbine Under Low Velocity Conditions

Water is a prime source to all living beings, but for humans it is even more because of its usage to extract power. The idea behind the water turbine is derived from the parental species of wind turbine. The operating fluid properties like density, specific weight of water draw out differences between the two turbine kinds. The objective of the present work is to experimentally investigate the performance of a two bladed Savonius water turbine with an aspect ratio of 1.21 at low water velocity conditions viz. 0.3 m/s, 0.65 m/s and 0.9 m/s. The variation of torque and power with the considered water velocities has been studied. Also a performance study has been conducted with the aid of Computational Fluid Dynamics (CFD) using Ansys 14.0. A detailed study on the flow characteristics has been done that elaborates the factors like torque variation at different angles of rotation of the turbine, revealing high torque generation at 270° position. Also the effect of tip speed ratio (TSR) on performance (Cp) has been studied and found that maximum Cp of 0.343 is obtained for water velocity of 0.65 m/s with a TSR of 0.643. The results obtained through CFD are in agreement with the experimental results.