Enhancement of a cycloidal self-pitch vertical axis wind turbine performance through DBD plasma actuators at low tip speed ratio

Abstract

Harvesting a maximum power from wind turbines especially at low tip speed ratio still remains a challenge. Vertical axis wind turbines (VAWTs) suffer periodically from stall which leads to aerodynamic losses and structural load fluctuation. In which improving their efficiency by increasing the generated power is an essential goal. The focus of the current study is to improve VAWT efficiency by analyzing the influence of using dielectric barrier discharge (DBD) plasma actuators on a cycloidal VAWT in combination with blade rotations and oscillations performance. The analysis is performed through computational fluid dynamics (CFD) and a user defined function (UDF) is loaded into ANSYS FLUENT to describe and control the complex dynamic pitching movements of the blades and the plasma effect. A sliding mesh technique coupled with the turbulence model k-ω SST is used in the simulations. The influence of the plasma actuation on the velocity contour, vorticity field and the evolution of power coefficient is analyzed. For better performance, a control law is proposed to regulate the plasma actuators operation as the blades rotate in azimuth direction. The results showed that by applying the DBD plasma actuation, with the control law, we can improve the power coefficient by 8% as compared to the base case and 38% as compared to a conventional fixed pitch vertical axis wind turbine.

Keywords

• DBD plasma actuator
• Wind energy
• Vertical axis wind turbine
• CFD
• Variable pitch angle
• Power enhancement