抄録
Vortex hydro turbines capable of generating power in small rivers and irrigation canals are used in Japan and abroad. The water guided to the casing swirls along the side walls and generates a vortex towards the drain hole provided at the bottom portion and is drained. The energy of this swirling flow is taken out as rotational energy by the runner to generate electricity, and the amount of power generation depends on the strength of the swirling flow. In this type of hydraulic turbine, the relation between runner shape and performance and the relationship between flow rate and power output have been studied and reported. In these reports, it is also reported that the swirling flow velocity and the free surface height are nonuniform in the circumferential direction. In this study, we investigated the relationship between casing shape and swirl flow velocity by gas-liquid two-phase flow simulation. As a result, we showed that the casing circumferential direction uniformity of swirl flow velocity and the free surface height is improved by using the eccentric casing.
