Application of rod vortex generators for flow separation reduction on wind turbine rotor

摘要

This paper focuses on flow control on wind turbine blades. A rod vortex generator (RVG) is proposed. Previous experimental and numerical results obtained for channels and blade sections proved RVGs to effectively enhance the streamwise shear stresses and reduce flow separation. The benefits of application of RVGs to control and decrease the flow separation on horizontal axis wind turbine rotor blades are assessed and presented in the paper. The numerical investigation was conducted with the FINE/Turbo solver from Numeca International, which solves the 3D Reynolds-averaged Navier-Stokes equations. The validation of the numerical model for the clean case is based on phase VI of the Unsteady Aerodynamics Experiment. At selected operating conditions, flow control devices have proven to reattach the flow locally to the wall and improve the aerodynamic performance of the wind turbine. Additionally, the local implementation of RVGs shows strong effect on flow structure and interaction with the main flow to create a shielding effect, preventing further penetration of separation towards blade tip. As a consequence, the positive effect of RVGs exists outside the blade span covered by devices. The obtained aerodynamic improvement shows that RVGs may be used as an alternative to traditional flow control devices applied on wind energy turbines.