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Wind turbines without pitch control are more preferable from economical point of view but aerodynamic stall affects them more and after a critical wind speed local boundary layer separation occurs. Consequently, their power production is relatively low. In this study, air ducts added on the blade and using the airflow from them the kinetic energy of the low-momentum fluid behind the surface was increased and delay of separation of the boundary layer from the surface was examined The Response Surface Optimization method was utilized in order to get the best possible design under the constraints and targets arranged for the parameters termed the diameter, slope, number and angle of attack of the air ducts. By using computational fluid dynamics analysis, optimum parameter values were obtained and air-ducted and air-duct free blade designs were compared. An improvement in power coefficient between 3.4–4.4% depending on wind speed was achieved with the new design. Due to increase in viscous forces, more power from the rotor obtained by opening air ducts up to a critical number. However, the results showed that after the critical number of air duct addition of more duct on the blade reduced the power coefficient.

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Due to greenhouse gases, we feel the effects of global warming more and more every day, so we need far more efficient Horizontal Axis Wind Turbines (HAWTs). This study was carried out to develop turbine blades with higher momentum coefficient (Cm) for the HAWTs. For this purpose, the blade profile that has higher performance was improved using Taguchi and Computational Fluid Dynamics (CFD) methods. With reference to the NACA 0012 profile, changing the upper and lower cambers of the profile derived the new blade profiles. Using the Taguchi method, the optimum blade profile with a maximum Cm coefficient was obtained. After the profile to be used on the turbine blades is determined, the blades are designed with the Blade Element Momentum (BEM) theory. A 3dimensional model for the HAWTs is developed using ANSYSv.16.2/Fluent Software. CFD analyses were performed using a sliding mesh approach to get more realistic and reliable results and to gain more knowledge of the performance. Numerical analysis results show that power coefficient (Cp) of the optimum profile is increased by 7.42% according to the NACA 0012 profile.