an axial hydro-kinetic turbine for optimum power extraction using tidal dams

The present paper describes analytical optimization and numerical simulation of a modern hydrokinetic turbine. it was a tidal turbine with twin ellipticrotors. the turbines were installed within the twin ducts inside of a tidal dam. there was a gap between each of the turbines and the ducts for allowing vortex formation around each of turbines. the pitch angle distribution was optimized for highest energy extraction from water flow. the numerical simulations of the turbine have shown great powercoefficient that exceeds from 1.0 for tipspeed ratios greater than 3.5. according to powercoefficient curve, the runaway speed for the hydrokinetic turbine was eliminated and the extracted power has increased with a second order function at higher tipspeed ratios. based on obtained data, an axial hydrokinetic turbine can not only absorb flow kinetic energy of incoming flow, but also can extract energy from parallel flows over each turbine. the powercoefficient curve against tipspeed ratio encounters with a break point around tipspeed ratio of 3.0. simultaneously a strong vortex ring has formed around each of turbines. flow trajectories illustrate how the hydrokinetic turbine was able to absorb much more energy from external flows than conventional axial hydro-kinetic turbines.