Flow Control Applied For Improved Performance of a Darrieus Type Wind Turbine

摘要

The focus of the present research is performance enhancement of a vertical axis, Darrieusrntype, wind turbine. The academic and industry interest in VAWTs is increasing due to itsrnsuitability to urban areas, characterized by high turbulence and low wind speeds. The paperrndescribes experimental work performed on a GOE-222 asymmetrical airfoil intended to be usedrnin a straight bladed Darrieus VAWT. Airfoil characteristics were measured in a wide range ofrnincidence angles and Reynolds numbers, relevant for the operation of a small to medium sizernwind turbine. A verity of passive flow control (passive porosity, surface roughness) and activernflow control techniques (boundary layer suction, pulsing suction) were tested in order to evaluaterntheir effects on the airfoil performance. The measured effects of flow control on the 2D airfoilrnare integrated into a modified version of a Double Multiple Stream-tube model in order tornpredict the effects on the performance and efficiency of the turbine.rnIt was found that the improvement of 2D airfoil characteristics can be translated intornhigher total turbine performances. By the use of AFC it was possible to increase the VAWTrnmaximum efficiency. When AFC optimization included the azimuth and Reynolds numberrnconditioning, the effects could be greatly increased while consuming less energy.