CFD analysis for the performance of micro-vortex generator on aerofoil and vertical axis turbine

A numerical study was performed to investigate the effects of Microvortex Generators (MVGs) on the aerodynamic performance of the NACA 0018 airfoil and an H-type Darrieus wind turbine. MVGs can delay stall, which may occur for a sustained duration during turbine operation. The flow fields around a single airfoil and the Vertical Axis Wind Turbine (VAWT) rotor are investigated. The purpose of the present work is to determine the best configuration of MVGs. In total, eight different configurations are studied. The results show that MVGs have significantly enhanced the lift of the airfoil near the stall and improve the stall margin. The improved airfoil design with MVGs installed at 20% chord length and 16° to the inlet flow with a rectangle shape has the maximum lift and stall angle. In addition, adding MVGs of the same configuration can significantly improve the power coefficient of the VAWT at a high tip speed ratio, where it typically gives low power production. The flow separation is suppressed in the azimuth angle ranging from 120° to 135°, where the power output increase is observed showing a potential impact for VAWT design.