Design of wind-turbine blades for improving aerodynamic performance using hybrid blades

Abstract

The blade airfoil significantly influences the performance of wind turbine. This study designs a new hybrid blade airfoil (abbreviated as HBA) based on the previous airfoils (S809 and NACA 63215). The surface-flow modes, wake-flow characteristics, and aerodynamic performance of HBA were tested using various Reynolds numbers and angles of attack. The experimental methods involved (1) the smoke-wire visualization at low wind speeds, (2) the surface-oil flow visualization at high wind speeds, (3) the hot-wire anemometry, and (4) the six force-moment balancer. At blade stall, the lift coefficient of 2.12 for HBA is approximately twice that of 1.07 for S809 and NACA63215. The maximum lift-drag ratio of 6.11 for HBA is approximately twice those (3.63 and 3.13) of S809 and NACA 63215. Moreover, the HBA has a higher stall angle than those of the other two blades. The (pitch) moment coefficient of HBA is also higher than those of S809 and NACA 63215.