Comparative Analysis of Savonius Type Ultra-Micro Hydrokinetic Turbine of Experimental and Computational Investigation

Abstract

Kinetic energy available in river streams can be harnessed to produce electricity in remote villages where power grid is unavailable. Savonius hydrokinetic turbine (SHKT) can be the solution to this issue as it is easy to construct, environment friendly and cost-effective. The performance of SHKT depends on the turbine geometry, the blade profile and the properties of the fluid. The experimental setup to evaluate the influence of these parameters in the laboratory can be very costly as it requires a huge water channel setup. Therefore, it is economical and timesaving to resort to computational analyses such as Ansys Fluent, Ansys CFX and OpenFOAM before experimenting. In the present study, the performance of the SHKT in terms of power coefficient (C_p) was performed computationally (both 2D and 3D) on the commercial CFD Fluent software. Commercial unsteady Reynolds-Averaged Navier–Stokes (URANS) solver with K-ω SST turbulence model was used for numerical analysis. For 2D and 3D CFD analyses, the turbine and blade particulars were taken from the work of Talukdar et al. [Talukdar et al. in Energy Conversion and Management 158:36–49, 2018] and Vimal et al. [Patel et al. in International Journal of Energy Research 41:829–844, 2017], respectively. Two-bladed Savonius turbines of semi-circular conventional blades were used to perform both the studies. The computational results of 2D and 3D were compared with the previous respective experiment results and there seemed to exist a good agreement in the 3D case (in 3D CFD, R² = 0.7 and 2D CFD, R² = 0.380). The deviaton of the computational value from the corresponding maximum experimental value (C_p) was found to be 38.9% in case of 2D CFD and 6.4% in case of 3D CFD.