Design and Numerical Investigation of a Small Axial Hydrokinetic Turbine

Hydrokinetic turbines are zero-head hydropower systems which use kinetic energy of flowing water to generate electrical energy. In the present paper the hydrodynamic performances of two axial hydrokinetic turbine designs having different geometries and operation conditions are analyzed. The aim is to obtain the largest power output from a water stream flowing with 1 m/s velocity using a 0.2 m tip diameter hydrokinetic turbine with three blades. As axial hydrokinetic turbines are lift-based turbines, the designs are developed by optimizing the total lift coefficient and thus obtaining the biggest power output for the given input data. Further, a detailed computational fluid dynamics study is performed using a low-order k-ω SST (Shear Stress Transport) turbulence model to determine the power output of the two designs. The results reveal the hydrodynamic behavior of the flow, i.e. the apparitions of a recirculation zone behind the runner blade and the power output of the different designs.