Abstract: In order to study the effect of leading edge wear on the aerodynamic performance of airfoil, a special-purpose airfoil S809 for wind turbines was taken as investigation object, and SST k-ω turbulence mode was used to carry out its numerical computation, and study the effect of different leading edge delamination depths on the flow field around airfoil and aerodynamic performance. The results show that the leading edge delamination will change the shape of the airfoil, so that the leading edge flow will become a step flow, causing the flow separation zone at trailing edge to expand and the separation point to move forward. With the increasing of the delamination depth and the angle of attack, the flow separation zone at trailing edge of airfoil on suction surface and the backflow vortex at leading edge of airfoil on suction surface will be changed from mutually independent state of each other to completely fused. Under condition of identical angle of attack, the leading edge delamination will have a greater influence on the pressure coefficient on the blade surface at the leading edge. When the angle of attack is less than 3°, the leading edge delamination will have little effect on the lift and drag coefficient of the airfoil. When the angle of attack is greater than 3°, the lift coefficient of the airfoil will gradually decrease as the degree of delamination becomes higher, but the drag coefficient will gradually increase. Compared to a smooth airfoil, the lift loss rate of airfoil with leading edge delamination will amount to its maximum of 55.08% and the drag growth rate 150.48%.

Key words: S809 airfoil, leading edge delamination, flow field around airfoil, aerodynamic performance