Design and cfd analyses of a spherical hydrokinetic turbine for energy production in pressurized water transmission lines

Energy demand has increased rapidly in recent years, with the technological developments. In this respect, scientists have focused on clean, renewable and sustainable energy sources in order to achieve a balance of energy supply and demand and to reduce the effects of global warming caused by increasing fossil fuel use. Hydropower sources have a special position among renewable energy sources due to their high predictability and high power potential. Hydrokinetic turbine technology has been developed in the recent years and hydrokinetic turbines do not need the construction of dam directly converging the energy of water to kinetic energy. The main purpose of this study is to design a spherical hydrokinetic turbine for converting excess pressure in gravity flowing water transport and transmission lines to electrical energy. In the design stage, numerical optimization of QBlade code has been achieved by considering geometric and dynamic parameters such as number of blades, blade profile, chord length, solidity, and tip speed ratio. Based on QBlade analyses and similar studies in the literature, 5-bladed spherical hydrokinetic turbine with NACA 0020 blade profile and 12 cm chord has been specified to be the final geometry of the present study. Computational fluid dynamics analysis of the proposed turbine have been provided by ANSYS CFX software inside on the pressurized water transmission pipeline domain and the fluid flow have been visualized. Finally, the effect of blockage on turbine performance has been analyzed and compared with the results of the previous literature studies.