Synthetical optimization design of rotor airfoil by genetic algorithm

According to the flight characteristics of helicopter and working environments of rotor, a group of airfoil design states, objective functions and constraint conditions suitable to the medium utility helicopter were proposed. The airfoil optimization was accomplished at multi-objective, multi-state and multi-constrain based on the classical rotor airfoil SC1095 used in "black hawk" helicopter (UH-60A) by genetic algorithm. The optimized rotor airfoil had larger camber and maximum thickness compared with the SC1095 airfoil. Results demonstrate that the pitching moment coefficient decreases by 57.2%, maximum lift coefficient increases by 3.7% and drag coefficient decreases by 7.5%. Meanwhile, there are some improvements of optimized airfoil aerodynamic characteristics under unsteady conditions compared with SC1095 airfoil. The areas of drag divergence and moment divergence of optimized airfoil decrease. After that, a rotor blade is constructed by using the optimized airfoil,results indicate that the FM (figure of merit) is increased and blade pitching moment coefficient is decreased compared with the baseline blade composed by SC1095 airfoil.