Numerical analysis of the effect of vortex generator on inboard region of wind turbine blade

Abstract

The blade design of a horizontal axis wind turbine (HAWT) prioritizes structural stability over aerodynamic performance, which results in power loss caused by stalling in the inboard regions. In this study, a vortex generator (VG) was employed for stall control. Because the generated vortex intensity varies with the VG geometry and size, design values based on the aerodynamic characteristics of airfoils in a wind turbine blade were considered. The VG design values for the HAWT were determined based on the computational fluid dynamics (CFD) analysis of the airfoil in the blade region with the maximum chord length. VG applicability was examined for all airfoils applied to the blade inboard region. Based on the lift and drag data obtained through the CFD analysis, the performance improvement of the wind turbine was analyzed through the blade element momentum theory. This analysis also incorporated the angle of attack of the airfoil, which differed for each local cross section in a wind turbine. The VG application increased the wind turbine power for each wind speed interval by an average of 2.5% and the annual energy production by up to 2.7%. The application of the proposed VG design to the inboard region can control the radial flow generated near the hub, improving the aerodynamic performance and decreasing the power loss.