A ducted Darrieus-type turbine has been proposed for hydropower utilization of extra-low head less than 2 m. Though the hydro turbine system, in general, might consist of an intake, runner casing section and a draft tube for higher efficiency operation, it was clarified in previous experiment that there was no need of the side-walls of runner casing section and a draft-tube for keeping the efficiency high in the case of duct with an inlet nozzle. This would yield a simplification of the structure of the turbine system. In order to reconfirm this result for large-sized turbine with 560 mm×300 mm duct, instead of small-sized one with 400 mm×200 mm duct, the side-wall effect on turbine performance was experimentally investigated for three- or four-bladed runner. In the present paper, the experimental results are shown with considering flow behaviors in the runner section.
All Science Journal Classification (ASJC) codes
- Materials Science(all)