应用协同射流原理的旋翼翼型增升减阻试验研究

协同射流技术作为一种新型主动流动控制技术，是突破旋翼翼型高增升减阻设计的最有潜力的发展方向之一。以 OA312 旋翼翼型作为基准翼型，研制微型涵道风扇组为驱动的旋翼翼型 CFJ 风洞测力模型，开展基于前缘高负压零质量内循环协同射流原理的旋翼翼型高增升减阻低速风洞试验，研究吹气口大小、吸气口大小和上翼面下沉量等基础参数对增升减阻的影响规律，探讨 CFJ 旋翼翼型关键参数最佳取值。结果表明：与OA312 基准翼型相比，小攻角状态时，CFJ 旋翼翼型可显著降低阻力系数，甚至出现“负阻力”现象，实现了零升俯仰力矩基本不变；大攻角状态时，CFJ 旋翼翼型可显著提升最大升力系数和失速迎角，其中，最大升力系数可提升约 67.5%，失速迎角推迟了近 14.8°。

Experimental Investigation of Lift Enhancement and Drag Reduction of Rotor Airfoil using Co-flow Jet Concept

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.