升力偏置对旋翼气动性能的影响

Influence of Rotor Lift-Offset on ABC Rotor Performance

采用共轴刚性旋翼的高速直升机是未来旋翼飞行器的发展方向之一,其本质特点即前行侧桨叶会产生升力偏置。为了研究旋翼升力偏置量对刚性旋翼性能的影响,采用自由尾迹方法对采用前行桨叶概念(Advancing blade concept,ABC)的刚性旋翼在不同升力偏置状态下的气动特性进行了计算。通过对计算结果的分析,得到旋翼升力分布、升阻比、阻力特性和功率特性等随升力偏置的变化规律。文中还对前进比μ=0.2,0.4,0.5的计算结果进行了对比分析。结果表明,旋翼升力偏置量的改变能够显著改变旋翼桨盘的升力分布,进而对旋翼气动性能产生重要影响。不同的前进比下,产生旋翼最大前飞升阻比的升力偏置量也会有所不同,μ=0.2时,最大前飞升阻比出现在旋翼升力偏置为20%左右;μ=0.4时,最大前飞升阻比出现在旋翼升力偏置为25%左右,μ=0.5时,最大前飞升阻比出现在旋翼升力偏置为30%左右。

The high speed coaxial helicopter with rigid blades will be the future of rotorcraft,which essential characteristic is the lift.offset of advancing blades. In order to research the influence of lift.offset on the rotor performance,the aerodynamic characteristics of advancing blade concept(ABC)rotor with different lift-offsets are calculated by the rotor free wake method. Through the analysis of the computing results,the effects of lift-offset on rotor lift distribution,lift.drag ratio,drag and power characteristics are obtained. The comparison and analysis of the results of advancing ratios μ=0.2,0.4,0.5 are also conducted. Results indicate that the rotor lift.offset plays a key role in the forward flight performance,thus changing the lift distribution on the rotor . The rotor lift.offset producing maximal lift.drag ratio varies with different advancing ratios. The maximal lift-drag ratio appeares at the lift.offset of about 20%,25%,30%when μ=0.2,0.4,0.5,respectively.