Performance improvement of straight darrieus type wind turbine by cylindrical guide

Abstract

In late years, from the viewpoints of drying up of fossil fuels such as oil or coal, and prevention of global warming, the renewable energy such as solar power generation or wind power generation attracts attention. The wind power generation can generate electricity with relatively low cost in renewable energy. A highly efficient propeller type wind turbine is generally used for wind power generation, but disadvantages are that the posture control to the direction of the wind is needed, and propeller type wind turbine is noisy. The Darrieus type wind turbine has the features that the control for wind direction is unnecessary, and the low noise, which is suitable for using in a residential area. In this paper we improve the performance of the wind turbine by mounting the cylinder type flow guide in a Darrieus type wind turbine. The guide ratio defined as the ratio of cylindrical guide diameter against wind turbine diameter was examined by experiment varying chord length. As a result, it was clarified that the wind turbine with guide ratio rd /ld=0.45, number of wings N=3, wing cord length lc=80 mm indicated the highest power coefficient Cpmax =0.172. Moreover the flow around wing was calculated by LES under the conditions with and without cylindrical guide. As a result, it was clarified that the performance of wind turbine with cylindrical guide was improved by decrease of separation on suction side wing surface.

Keywords

• wind turbine
• darrieus
• cylindrical guide
• performance improvement
• experiment
• cfd