Comparative investigations for performance and self-starting characteristics of hybrid and single Darrieus hydrokinetic turbine

Hydrokinetic turbine technology is an emerging field to produce clean energy from the riverine systems. Lot of hydrokinetic potential sites are available to provide the energy to the people living in those areas. Under the present work, two different hydrokinetic turbine rotors (hybrid and single Darrieus) are evaluated in term of performance and flow across the rotor. The flow velocity of water is considered as 1.0m/s and the model for both type of rotors are designed and modeled along with an open channel. Based on the investigations, it has been found that hybrid rotor is more efficient for hydrokinetic turbine and yields about 9.9% higher power coefficient (C-P) than single Darrieus rotor. The average torque coefficient (C-T) for hybrid rotor has also been found 15.9% higher than single Darrieus rotor with less fluctuations in torque. The results obtained from the numerical investigations are validated with experimentation results. Flow contours across the turbine rotor were plotted and smooth flow was observed with low-pressure range for hybrid rotor while the single Darrieus rotor experience a flow re-circulation zone with high-pressure range. (C) 2019 Published by Elsevier Ltd.