基于CFD的分段翼型控制研究

为提升流体机械在非设计工况下的性能,借鉴飞行器起飞阶段通过调节前缘缝翼来提高升阻比的思想,设计了一个可调前缘缝翼的分段翼型.利用稳态CFD模拟建立输入变量（前缘缝翼的偏转角度、重叠量和缝道宽度参数）与输出变量（翼型升阻比）之间的数值模型,通过遗传算法以不同攻角下最高升阻比为目标对各个参数进行寻优,建立了来流攻角与最优缝翼位置间的对应关系,从而为实现流动的主动控制提供理论依据.对分段翼型的研究表明：应用遗传算法优化缝翼参数能提高计算效率,其计算次数仅为全部计算的40%左右.优化的缝翼参数有效地改善了翼型的气动性能,与原始翼型相比通过调整前缘缝翼位置提高了其在大攻角下的升阻比,可为设计多工况高效流体机械提供参考思路.

Study on control of multi-element airfoil based on CFD

To improve the performance of fluid machinery at off-design conditions,a multi-element airfoil with adjustable leading edge slats was designed inspired by the idea of improving lift-drag ratio of aircraft by adjusting the leading edge slats at take-off stage.The numerical model of the inputs（deflection of the leading edge slats,overlap and gap） and output（the lift-drag ratio of aircraft） was established based on CFD numerical simulation of steady flows.Those three input variables were optimized through the genetic algorithm to get the maximum lift-drag ratios in different angles of attack.The relations between angle of attack and slats position for an optimal lift-drag ratio were established,providing a theoretical basis for active control of flow.The results show that using genetic algorithm to optimize the slat parameters can reduce time-consuming as high as 40%.The aerodynamic performance of multi-element airfoil was greatly improved through optimizing slats parameters.As a result,the lift-drag ratio at a large angle of attack was raised compared with the original airfoil.This work can provide a reference for designing fluid machinery with high-efficiency under multi-conditions.