Application of Vortex Generators to Wind Turbine Blades

Abstract

The application of an array of vortex generators (VGs) to control flow separation and mitigate blade soiling problems of wind turbines was studied using the commercial CFD software AcuSolve. In order to model the blade soiling effect, a roughness model was implemented in AcuSolve and validated with the wind tunnel test data from Ohio State University (OSU) [1 and 2]. The predicted aerodynamic surface pressure and forces from CFD agreed well with wind tunnel test data. Further investigation showed that air flow over an airfoil section under roughness effect with vortex generators can be simulated with CFD techniques with reasonable accuracy. The case study of an NREL 5-MW wind turbine demonstrated that total power loss per year due to the leading edge contamination can go up to 6.6%. It suggested that VGs can be used to improve wind turbine performance and result in 1.0% increase in annual energy production (AEP) by suppressing the flow separation and mitigating the soiling effect. The placement of vortex generators along the blade span is critical to overall turbine performance.