Abstract: To optimize the aerodynamic performance of compressor blades, we propose a leading edge design method based on curvature distribution control, realizing direct and precise control of the leading edge curvature. This design method is applied to the Controlled Diffusion Airfoil (CDA) of an industrial compressor, and the performance of the airfoil with the designed Mach number at all incidences is calculated by the numerical simulation method. The results show that increasing the curvature of the leading edge can effectively broaden the allowable incidence range and reduce the peak diffusion factor. At the same angle of attack, the optimized airfoil can weaken the leading edge suction peak, suppress or even eliminate the separation bubble, and avoid the occurrence of early transition. Meanwhile, adjusting the curvature distribution to make it as "full" as possible and slowing down the decrease rate of curvature in the vicinity of the leading edge point can achieve the same effect. Theoretical analysis reveals that the curvature of the leading edge affects the initial flow pattern of the boundary layer by adjusting the static pressure distribution, therefore affecting the performance of the blade as well. In designing the leading edge geometry, it is necessary to ensure the curvature continuity, adjust the curvature distribution to reduce the strength of the leading edge suction peak, thus avoiding the occurrence of separation-induced transition.

Key words: curvature distribution, compressor blades, profile loss, boundary layers, separation-induced transition