Performance evaluation of a drag hydro kinetic turbine for rivers current energy extraction - A case study

River current energy is considered as the greenest energy available, as it has enormous energies stored. It is a promising energy source in renewable energy due to the accessibility and availability. The River Nile in Egypt has been selected in this work as the case study for this kind of energy. The process of hydro-kinetic energy conversion utilizes the contained kinetic energy in the river stream which can be extracted by a submerged vertical axis turbine. The main objective of this work is to design and simulate a water current stream energy conversion system as a stand-alone power station for the electric power generation. The generated electric power is intended for rural and domestic applications. CFD is used to simulate and redesign a drag turbine. The numerical analysis indicates that the S shape blade has the maximum power coefficient of 24.6% for a tip speed ratio 0.8 and streamflow velocity 3 m/s. The results indicate that the maximum power coefficient of the S shape and the conventional design are 18% and 12.8% respectively at the tip speed ratio 0.8 and 0.5 m/s. The S shape enhances the turbine performance by 40% compared with the conventional design, especially at low velocity.