Hydrokinetic hybrid vertical axis rotor performance at difference blade shape and angles of attack

Abstract

We must invest in renewable energy research to combat pollution from fuel combustion and promote affordable energy. Hydrokinetic rotors produce mechanical torque using kinetic energy in rivers, canals, and ocean water. Hydrokinetic integrated Darrieus-Savonius rotors are a vertical axis type with good properties, but only a few researchers are interested in them. Only one Savonius rotor has the ability to self-prime, despite having poor performance but high torque. Darrieus rotors are effective but challenging to start. In order to find the best configuration, hydrokinetic integrated rotor performance is experimentally studied in this work. The study was conducted in a water flume at Egypt's National Water Research Centre, Hydraulics Research Institute (HRI). The number of Darrieus blades, Darrieus blade attack angles, and airfoil shape are studied and compared for four different NACA airfoils: NACA 012, 015, 018, and NACA 021. Semi-circular Savonius blades were employed in this work, the fact that the Savonios rotor in double-stage is always the best in terms of performance for an integrated rotor. The results showed that NACA 21 with a three-bladed Darrieus rotor and 15° angle of attack produced the highest power factor, as the maximum obtained value is 0.334 at a tip speed ratio of 1.8.