Investigation on Torque Coefficients of Horizontal Axis Wind Turbine with Symmetrical and Asymmetrical Split-tip Winglets

Abstract

This study examines the aerodynamic characteristics of circular arc blade sections (CABS) in horizontal axis wind turbines (HAWT) by exploring the effects of symmetrical and asymmetrical split-tip winglets. The research entails conducting experiments to investigate different pitch angles (фP) and tip speed ratios (λ), while keeping a cant angle of 50° and a split-tip height equivalent to 6% of the rotor radius, as previously determined in existing studies. The investigation involved an analysis of the torque coefficients, identifying the most optimal arrangement at a tip speed ratio of 4. The findings suggest that the asymmetrical split tip produces a torque that is 5.33% greater than the reference model when operating at a tip speed ratio of 4 and a pitch angle of 0°. In the same way, the symmetrical split-tip configuration exhibits an increase in torque of 8.1% when subjected to a pitch angle of 2° and tip speed ratio 4. When the pitch angle was set at 0°, the symmetrical split tips exhibited an average torque increase of 9.61%, while the asymmetrical split tips showed a torque increase of 6.95%. Similarly, at a pitch angle of 2°, the symmetrical split tips experienced an average torque increase of 9.81%, while the asymmetrical split tips showed a torque increase of 7.27%.

Keywords: Renewable energy, wind turbine, HAWT, winglet, split-tip, and torque coefficient