Effect of Exit Blade Angle on the Performance of Cross Flow Hydro Turbine: A Numerical Study

Cross-flow hydro turbines (CFHTs) are generally used in micro hydraulic power plants due to their simplicity in design and fabrication, moderate efficiency, ease of maintenance. The CFHT can be used in low flow and low head conditions with an efficiency of around 90% at rated conditions. However, the efficiency of the CFHT can further be improved by changing its geometric parameters Hence, in the present investigation, 3D unsteady simulations are performed in order to locate the exit blade angle (β₂) with the intention is to improve the efficiency of the turbine. In the proposed investigation, the multi-physics FVM solver ANSYS Fluent has been used with the help of the SST k-ω turbulence model to carry out the unsteady simulations. The 3D unsteady simulations are performed by varying the exit blade angle (β₂) from 60° to 90° to improve its efficiency when the rotational speed is fixed with the number of blades being 20. From the unsteady simulations, the maximum efficiency of the CFHT is at the exit blade angle (β₂) = 80°.