The Performance Improvement Effect of the Deflector Setting to Straight Darrieus Water Turbine in Narrow Channel

The performance improvement of the straight Darrieus water turbine has been needed to practical use for the small hydroelectric generator. Especially in a narrow channel, we suggested the setting the deflector (flat rectangular plate) at upstream of the turbine. To examine the performance improvement effect, we performed the torque measurement experiments and three dimensional numerical simulation of flow. All tested deflectors caused the change of the flow pattern compared to the without deflector. As results, it was clear that the most suitable aperture ratio (The aperture width divided by the channel width) is 60 % and the most suitable setting angle is 90 deg.