Design of a Horizontal Axis Wind Turbine

Abstract 

This project involved the design and Computational Fluid Dynamics (CFD) validation of a 660 W horizontal-axis wind turbine (HAWT) intended to supplement renewable energy generation and reduce dependence on fossil-fuel-powered generators. After completing the analytical design of the turbine geometry, airflow characteristics, and expected aerodynamic performance, ANSYS Fluent was used to investigate the real fluid behavior around the turbine blade under realistic operating conditions. The numerical simulations provided detailed insight into pressure distribution, velocity variation, turbulence development, wake formation, and aerodynamic loading, enabling validation of the theoretical design while demonstrating the capability of CFD to predict the actual performance of renewable energy systems.

Methodology 

The project began by determining the required turbine specifications, including a target output of 660 W, rotor diameter, blade length, hub height, and operating wind speed through analytical fluid mechanics calculations. A NACA 2424 airfoil was selected as the blade profile because of its favorable lift characteristics. The airfoil geometry was then imported into ANSYS Fluent, where a two-dimensional computational domain representing the surrounding airflow was created. A high-quality mesh consisting of approximately 154,768 cells was generated to accurately resolve the boundary layer around the blade. Air was defined as the working fluid using realistic density and viscosity values, while the SST k-ω turbulence model was selected to capture turbulent flow behavior. Appropriate inlet velocity, outlet pressure, wall conditions, transient solver settings, and second-order discretization schemes were specified before the solution was iterated until all residuals converged. Finally, contour plots, vector fields, and aerodynamic coefficients were extracted for engineering interpretation and design validation.

Simulations 

ANSYS Fluent simulations focused on evaluating the aerodynamic performance of the wind turbine airfoil under realistic wind conditions. CFD analyses included mesh quality assessment, residual convergence monitoring, velocity vector visualization, turbulence viscosity ratio contours, dynamic pressure contours, streamline (stream function) visualization, and several flow-field contour plots illustrating airflow around the blade. The simulations also calculated the lift coefficient (Cl) and drag coefficient (Cd) to quantify aerodynamic efficiency. Together, these visualizations revealed flow acceleration over the suction surface, pressure differences across the airfoil, turbulent wake development, and vortex formation, providing comprehensive validation of the wind turbine's aerodynamic behavior.

Results 

The simulations converged successfully, with all governing equations reaching residual values well below the specified convergence criteria, indicating numerically stable solutions. The turbine airfoil achieved a lift coefficient of approximately 0.583 and a drag coefficient of approximately 0.049, demonstrating an efficient lift-to-drag ratio suitable for energy extraction. Velocity and pressure contours showed accelerated airflow over the upper blade surface and reduced pressure responsible for lift generation, while wake contours confirmed energy extraction downstream of the blade. Turbulence visualizations revealed localized vortex formation near the trailing edge, consistent with the predicted turbulent flow regime and validating the analytical calculations used during the turbine design process.

Conclusion

The ANSYS Fluent simulations successfully validated the aerodynamic design of the proposed 660 W horizontal-axis wind turbine. CFD results closely agreed with the analytical calculations by confirming the expected pressure distribution, lift generation, wake formation, and turbulent flow behavior around the blade. The relatively high lift coefficient together with the low drag coefficient demonstrated that the selected NACA 2424 airfoil is suitable for efficient wind energy conversion under the design conditions. Beyond validating theoretical predictions, the simulations provided detailed visualization of complex flow phenomena that cannot be captured through analytical methods alone. Overall, the project demonstrates how CFD serves as a powerful engineering tool for optimizing renewable energy systems before prototype development, increasing confidence that the proposed turbine can contribute effectively to clean and sustainable electricity generation.