Aerodynamic performance of a horizontal axis wind turbine with forward and backward swept blades

Blades are the most important components of wind turbines in order to convert wind energy to mechanical energy. This study investigates the aerodynamic performance of Horizontal Axis Wind Turbines (HAWTs) with forward and backward swept blades. The effect of the blade sweep direction, the location of the sweep start up and the tip offset on the aerodynamic performance are investigated using a model HAWT with a 0.9 m rotor as the baseline configuration. Changes in power and thrust coefficients with swept blades are investigated for the design tip speed ratio of the baseline wind turbine at a wind speed of 10 m/s. The wind turbine with the forward swept blade that has sweep start up at r(ss)/R = 0.15 and tip offset of d/D = 0.2 has been found to give a remarkable boost to the power output with an increase of about 2.9% over the baseline turbine. The backward swept blade with r(ss)/R = 0.75 and d/D = 0.2 has shown the highest reduction in thrust coefficient, namely 5.4%, at the design tip speed ratio. In conclusion, it is found that the forward swept blades have the ability of increasing the performance while the backward swept blades tend to decrease the thrust coefficient.