旋翼非定常动态失速的三维效应分析

采用建立的高精度计算流体动力学(CFD)方法,针对旋翼非定常动态失速的三维（3D）效应特性进行研究。以Helishape 7AD旋翼为基准,开展三维效应对旋翼非定常气动特性的影响分析。研究了来流马赫数对旋翼翼型动态失速特性影响。在此基础上,针对三维情形旋翼动态失速非定常涡流动特性及诱导分离特征开展了数值分析,通过与二维情形对比表明:受旋翼旋转、轴向诱导速度等三维效应影响,旋翼桨叶剖面动态失速涡的产生、对流和脱落明显滞后于二维翼型情形,并且涡强度也更弱。越靠近桨叶内段,桨叶剖面非定常动态失速特性与二维旋翼翼型情形的差距越为明显。 

Analysis on three-dimensional effects of rotor unsteady dynamic stall

A CFD method with high precision was adopted to investigate the characteristics of three-dimensional (3D) effects of flow on rotor dynamic stall. The Helishape 7AD rotor was taken as example, and the influences of three-dimensional effects on rotor unsteady aerodynamic characteristics were researched. The effects of inflow Mach number on dynamic stall of rotor airfoil were investigated. On these bases, characteristics of unsteady vortex and induced flow on rotor dynamic separation were numerically analyzed, and the comparisons with the 2D states indicated that due to the effects of the rotation of blade and axial-induced velocity, the formation, convection and shedding of dynamic stall vortex on rotor blade section delayed compared with the 2D state of airfoil, and the intensity of vortex was weaker. As blade section was closer to root of rotor, differences for characteristics of dynamic stall between rotor blade section and the 2D state rotor airfoil were more obvious.