微型飞行器桨翼气动干扰的数值模拟

Numerical Simulation of Propeller-wing Interaction on MAV

对某一固定翼微型飞行器进行了桨翼气动干扰数值模拟研究,采用作用盘理论模拟真实桨盘的工作状态,通过时间平均稳态处理将非定常流场简化为准定常流场计算。利用FLUENT的用户自定义函数UDF实现作用盘前后压力、速度的变化。通过与无滑流影响下单独机身数值计算结果的比较,结果显示螺旋桨滑流延缓了机体上表面的气流分离,增强气流再附着能力,飞机的失速迎角增加2°,升力、阻力、俯仰力矩系数增加2%～5%,升阻比减小2%～3%。

A computational study has been performed on the aerodynamic influence of a tracer propeller installed on a MAV（micro air vehicle）.An Actuator Disk model of a propeller which employs uniform pressure jump and velocities differences has been developed to simulate real propellers,hence,the inherently unsteady flow can be simplified into a quasi-steady one.FLUENT,a commercial CFD tool,has been used to investigate the flow around a low-aspect-ratio MAV with UDF（users′defined function）.Compared with a clear MAV,the propusion effect has been observed to retard the flow separation on the upper surface by 2 degrees and to promote the re-attachment of the separated flow,which contribute to the increases in lift,drag and pitching-up moment about 2%-5% with the actuator disk on.The lift-to-drag ratio has been observed to be slightly lowered by the introduction of the actuator disk.