Guide Vanes for Darrieus Water Turbine in Tidal Current

On purpose to enhance the performance of a Darrieus-type water turbine for the power generation using a tidal current, the technique with guide vanes were applied. The guide vanes placed in front of the turbine, were expected to allow the turbine to rotate with higher speed by turning the direction of the current partially. The device was tested in both the wind and water tunnels, and its effect was recognized at both tests. Since the configuration with the twin turbines in parallel was considered advantageous especially under the weaker tidal current, the guide vanes suitable for the twin-turbine configuration were investigated using the wind tunnel, based on the previous results obtained in the single-turbine configuration. The experimental results showed that the guide vanes placed on the center line increased the rotational speed in the regions of lower tip-speed ratio.