旋翼滑流对倾转旋翼机飞机模式下气动特性的影响

建立了考虑旋翼桨叶形状、桨叶片数、桨距和转速等因素的等效桨盘模型,该模型中桨叶对气流的作用被等效为时间平均的源项添加到控制方程中,并通过两个算例验证了模型的有效性。对V-22倾转旋翼机飞机模式高速巡航状态下的全机三维流场进行了数值模拟,分析了旋翼流场特征,定量给出了滑流对气动力系数的影响量。计算结果表明:旋翼滑流明显改变了机翼表面的压力分布,使全机升力系数增大,最大升力系数增量为4.6%；0°迎角下滑流使阻力系数减小了29%,而4°迎角后,滑流使得阻力系数增大,在14°时增量达到了32%；俯仰力矩系数的变化量为4.6%。进一步研究发现,滑流对平尾下表面压力系数分布产生较大影响,而对垂尾影响则较小。 

Rotor slipstream effects on aerodynamic performance of tiltrotor aircraft in airplane mode

An equivalent actuator disk model was developed by taking into consideration such factors as the blade shape, the number of blade, blade pitch and rotating speed of rotor. This technique modelled the rotor implicitly through time averaged source terms in the equations and two test cases were used to validate the actuator disk model. The three-dimensional flow field around V-22 tiltrotor aircraft in high-speed airplane mode was simulated. The characteristics of the rotor flow field were analysed and the increments of aerodynamic coefficients caused by slipstream were also presented. The results showed that the rotor slipstream altered the pressure distributions on wing surface evidently, which increased the lift coefficients up to 4.6%. Slipstream decreased the drag coefficients about 29% at 0° angle of attack. However, after 4° angle of attack, slipstream increased the drag coefficients and the maximum increment was up to 32%. The variation of the pitching moment coefficient was also 4.6%. Further studies show that rotor slipstream has greater effect on the lower surface of the horizontal tail, while making a small impact on the vertical tail.