Aerodynamic Impact of Blade Pitch Angles on Wind Turbine Efficiency: A CFD Study Using ANSYS<br />Eng. Nourhan Thamer Assi<br /><br />Relevant Sustainable Development Goals (SDGs)<br />Goal 7: Affordable and Clean Energy<br />Goal 9: Industry, Innovation, and Infrastructure<br />Goal 13: Climate Action<br /><br />Blade pitch angle—the angle between the blade chord line and the plane of rotation—is a critical parameter influencing the aerodynamic performance of wind turbines. Adjusting the pitch angle optimizes the lift-to-drag ratio of the blades, thereby maximizing power output and protecting the turbine from extreme wind conditions. This study uses Computational Fluid Dynamics (CFD) simulations performed in ANSYS Fluent to investigate how varying blade pitch angles affect wind turbine efficiency.<br />Background and Importance<br />Wind turbines operate in highly variable wind conditions, and the ability to adjust blade pitch dynamically is essential for maintaining optimal performance. Pitch control not only affects aerodynamic forces but also influences fatigue loads and overall turbine lifespan. Understanding these aerodynamic impacts through detailed CFD analysis supports better turbine design and control strategies.<br />Simulation Setup<br />The turbine model consisted of a three-blade horizontal-axis rotor with realistic aerodynamic profiles. Simulations were conducted for blade pitch angles ranging from 0° to 20° at a constant wind speed of 10 m/s. The flow domain was meshed with fine resolution near the blades to capture boundary layer effects. The k-ω SST turbulence model was employed to resolve the complex flow features around the blades.<br />Results and Findings<br />At 0° pitch angle, the turbine showed moderate power output with relatively stable flow, but the lift forces were not maximized.<br />Increasing pitch to 5° resulted in the highest power coefficient (Cp) and torque, indicating optimal aerodynamic efficiency.<br />At 10° pitch, power output began to decline slightly due to early onset of flow separation near the blade tips.<br />Beyond 15° pitch, significant flow separation and turbulence were observed, causing a sharp drop in efficiency.<br />At 20° pitch, the blades experienced stall conditions with high drag forces and dramatically reduced lift, leading to a major loss in power.<br />Flow visualization showed smooth streamlines and strong pressure differentials on the suction side at low pitch angles, while higher pitch angles exhibited turbulent wake regions and recirculation bubbles.<br />Implications for Turbine Operation<br />The study confirms that precise control of blade pitch angles is essential for maximizing energy capture and minimizing aerodynamic losses. Real-time pitch adjustment mechanisms can optimize performance across varying wind speeds and reduce mechanical stress, improving turbine durability and efficiency.<br /><br />Conclusion<br /><br />The CFD investigation using ANSYS Fluent demonstrated that a blade pitch angle near 5° offers the best balance between lift generation and drag reduction for the examined wind turbine model. As pitch angles increase beyond this point, aerodynamic efficiency decreases due to flow separation and stall. These insights support the development of advanced pitch control systems to enhance wind turbine performance and contribute to the advancement of sustainable energy technologies.<br />Al-Mustaqbal University – The No. 1 Private University in Iraq