Kazuki Takenouchi

Two-dimensional flow analysis in a Darrieus-type water turbine with arbitrary-shaped duct

One solution method for an inviscid flow field of a two-dimensional Darrieus-type runner in an arbitrary-shaped duct and a draft tube is proposed in the present paper. This computation consists of two stages. As the first stage, the flow through the duct is analyzed by a panel method with vortices distributed on the duct walls and the stream function and velocity potential are obtained at any position in the physical plane. Using these values the flow field is transformed to the reflected plane of flow with parallel walls as the stream function on the wall becomes constant. The induced flow due to bound and released vortices of the Darrieus blades is analyzed by the image method in the second stage. The evaluated Darrieus blade characteristics from the measured data with this solution and the calculated flow distortions due to the blade behavior are shown and discussed for ducts of various shapes.