Abstract
A Darrieus-type hydro-turbine system has been developed for hydropower utilization of extra-low head less than 2m. When the Darrieus-type hydro-turbine was installed in open channel, an increase of torque coefficient was observed with installing inlet nozzle. Especially, an installation of two-dimensional symmetric Straight Line Nozzle (SL Nozzle) with the converging angle of 45°produced larger torque than that of two-dimensional symmetric Half Diameter curved Nozzle (HD Nozzle). In the present study, in order to understand a cause of the difference of torque characteristic between SL Nozzle and HD Nozzle, two-dimensional numerical simulation is carried out. The relation between torque characteristics and the flow around rotating Darrieus blade is discussed.
