Abstract:Rotor airfoil design involves multi-point and multi-objective complex constraints. How to significantly improve the maximum lift coefficient and maximum lift-to-drag ratio of rotor airfoil is a fundamental problem to be solved urgently in the development of high-performance helicopter rotor blades in the future. Novel flow control technology is the most potential method to achieve the high lift enhancement and drag reduction of rotor airfoil. Based on the classic OA312 rotor airfoil, this paper conducts the low-speed wind tunnel test of high lift enhancement and drag reduction of rotor airfoil using Co-flow Jet concept (CFJ) with zero mass and high negative pressure at the leading edge. The rotor airfoil CFJ dynamometric model driven by the micro ducted fan group is designed. The influence of basic parameters such as the injection size, suction size and suction surface translation on lift enhancement and drag reduction is studied. The ratio of jet velocity to mainflow velocity is qualitatively discussed. The optimal value range of key parameters of CFJ rotor airfoil is given. Results show that compared with the OA312 baseline airfoil, the CFJ rotor airfoil can significantly reduce drag coefficients at low angle of attack, and even achieve while the zero-lift pitch moment is basically unchanged. The CFJ rotor airfoil can significantly increase the maximum lift coefficient and the stall angle of attack at high angle of attack. The maximum lift coefficient can be increased by about 67.5%, and the stall angle of attack is significantly delayed by nearly 14.8°. Research results verify the technical feasibility of applying CFJ technology to significantly improve the key performance of rotor airfoil and provide a new feasible solution and idea for the design of high-performance rotor blades in the future.