Enhancing Dual-Rotor Vertical Axis Wind Turbines with Auxiliary Augmentation: Impact of Deflector Angle Orientation

Abstract This study examines the effect of deflector angle orientation on the performance of a Dual-Rotor Straight Blade Vertical Axis Wind Turbine (DR-SBVAWT). Using Computational Fluid Dynamics (CFD) simulations, we analyze the impact of various deflector angles as an auxiliary augmentation on turbine efficiency. A 2D transient simulations were performed for this parametric study. The results demonstrate that a vertical deflector, β = 0° (from Y-Axis), yields the best performance, providing the highest efficiency and power output. In contrast, a horizontal deflector (angle of β = 90° counterclockwise from Y-Axis) shows minimal impact on the turbine's performance, suggesting that further angle variations do not significantly enhance the system. Moreover, sensitivity analysis was performed to evaluate the impact of small changes in the deflector orientation that shows β = 0° holds the best orientation, and small angle variations in deflector orientation show minimal impact on the overall performance of the turbine. In steady-state conditions, the vertical deflector angle increases the Tip Speed Ratio (TSR) of the DR-SBVAWT performance by 6 % compared to the base angle at β = 55°, or 11.5% compared to a conventional dual rotor without deflector. Additionally, this configuration achieved a 30.15% increase in efficiency at TSR = 2.5, showing its effectiveness in improving overall aerodynamic performance. This parametric study overall provides valuable insights into the optimal deflector angle configuration as an auxiliary augmentation system for dual-rotor vertical axis wind turbines, contributing to the design optimization and improved performance of wind energy systems.