桨尖开孔参数对旋翼流场特性的影响研究
Investigation of Slotted Tip Parameters on the Aerodynamic Characteristic of Helicopter Rotor

采用CFD数值模拟方法开展了基于桨尖开孔的旋翼桨尖涡抑制研究，重点分析了开孔位置、数目、直径等参数对桨尖涡结构和旋翼气动性能的影响。旋翼流场数值模拟通过求解旋转坐标系下的Navier-Stokes方程，采用格点格式的有限体积法，结合非结构重叠网格技术。无黏通量计算采用二阶中心格式加人工耗散，湍流模型采用Spalart-Allmaras模型。数值研究表明：桨尖开孔的位置对桨尖涡削弱效果的影响很小；开孔数目越多，孔径越大，桨尖涡的削弱效果越好；开孔旋翼的升力系数较无开孔构型小幅增加，而功率系数则较大幅度增加。
Numerical simulations are conducted to investigate the effect of helicopter rotor tip vortex alleviation using a slotted tip, and effects of parameters involving location, number, aperture of the slot on tip vortex structure and aerodynamic performance are analyzed in detail. The flow field of hovering helicopter rotor is simulated by solving Navier-Stokes equations in the rotating coordinate system. Finite volume method combined with overset unstructured grids algorithm are adopted. The calculation of inviscid fluxes uses second-order central scheme with artificial dissipation, and turbulence model utilizes Spalart-Allmaras model. Simulation results show that the location of the slot has little effect on tip vortex alleviation. The larger the number and aperture of the slot, the better the effect of slotted tips weakening tip vortex. Lift coefficient of helicopter rotor with a slotted tip increases slightly compared with that without slots, while power coefficient increases drastically