Abstract
To improve the performance of nondirectional vertical-axis windmills, we propose using a cylindrical wind collector with the vertical-axis windmill type. The collector is placed around the wind turbine rotor shaft in order to accelerate the wind speed near the blades. In this study, windmill performance with the prototype wind collectors was investigated experimentally. The collectors that were designed had one of three diameters: 140, 165, or 216 mm. The length of the arm of the windmill was 20 mm longer than the diameter of the associated collector. The apparatus used in this study were a Gottingen-type wind tunnel, digital tachometer, and pitot tube. As a result of the experiment, it was found that the windmill with a collector was better than that of a non-collector windmill, for all collector diameter conditions. In addition, as the collector diameter became larger, the wind velocity at which a windmill began to revolve decreased.
