Numerical prediction of the performance of axial-flow hydrokinetic turbine

The present work is focused on the numerical prediction of the performance of axial flow hydrokinetic turbine under practical conditions. The models are designed to produce an electrical power output of 200 W at an incoming water speed of 1 m/s. Three different models of three-bladed turbine, based on swept direction, are designed to study the effect of geometry on the turbine performance while operating under identical conditions. Numerical simulations indicate that a peak turbine power of 480 W at a tip speed ratio of 3.5 is obtained for unswept bladed turbine with sharp trailing edge. Results suggest that forward and backward swept blades perform better than the unswept blade for blunt trailing edge. Simulations are carried out for different nose profiles for hub. It is found that a turbine experiences lesser thrust force with an ellipsoidal nose having ratio of major axis to minor axis of 4. In order to capture a real life scenario effectively, the effect of turbine location inside the water, particularly with respect to the free surface is investigated further. The safe depth for turbine installation is found to be at least 1.4 m from the free surface.