微型飞行器桨翼气动干扰的数值模拟

摘要

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廷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.