扇翼流动机理数值模拟研究

以扇翼的气动特性(高升力)为关注焦点,对扇翼流动的流场结构细节进行了数值模拟研究。对有推力二维Lockheed C-141超临界翼型进行数值模拟,验证和确认了扇翼流场的数值模拟方法,并数值模拟了扇翼旋转时的流场结构。结果表明,其高升力来源于固定翼部分上表面高速流动的射流,而这种射流正是由叶片旋转带动扇翼内部流体不断加速喷射得到的。扇翼内部的流动是复杂的非定常流动,存在多种尺度的旋涡、湍流边界层及二者的相互干扰等,使气动力高频振荡,进而可以预测相当的气动噪声是不可避免的。将算法应用于扇翼飞行器的外形设计优化阶段,得到了若干构型的气动性能,为下一步开展的无人机研制工作提供了指导。

Numerical Simulation of Fan Wing Cross-flow Mechanism

Focusing on the high lift mechanism of the fan-wing system , a numerical simulation work is conducted ,yielding the flow field details of the cross-flow structure .To verify and confirm the method of simulation ,the Lockheed C-141 foil with thrust device is simulated ,which shows a good match with other′s data.After then,a fan-wing configuration is simulated with the exactly same method ,and a conclusion is made as follow .The high lift mechanism of the fan-wing system is come from the jet flow above the upper surface of the fixing wing ,which is generated by the blade rotating of the fan .The inner filed within the fan region is unsteady flow ,with all kinds of scales of vortices ,turbulence boundary layers and the interference between the them ,which makes the aerodynamic forces oscillating with high frequency . As a result,aerodynamic noise is inevitable .At last,an optimization work is done using method above , which generates a better configuration for the next phase of work for the UAV design .