复杂几何细节对增升装置气动性能影响研究

 采用数值模拟的方法研究了主翼翼根几何形状、翼吊发动机短舱、缝翼滑轨及襟翼滑轨舱等几何细节对增升装置气动性能的影响。研究结果表明:切割前缘缝翼时,将大部分翼根整流包留在主翼上会在大迎角下产生低能量的分离涡,造成增升装置气动性能显著恶化,而将大部分翼根整流包切割到前缘缝翼上,能破坏低能量分离涡的产生;大迎角下,短舱上表面、挂架表面及缝翼与挂架之间的间隙产生的分离气流会直接流到主翼上表面,形成大范围的死水区,因此,大尺寸的翼吊发动机短舱会造成增升装置失速迎角及最大升力系数的大幅减小,但安装在短舱适当位置、适当形状的涡流片产生的强漩涡能消除大部分的死水区,挽回部分气动性能损失;缝翼滑轨产生的低能量尾迹会混入主翼附面层,使其能量降低造成升力系数减小,极端情况下缝翼滑轨会直接诱发大范围的流动分离,造成增升装置气动性能的显著恶化;襟翼滑轨舱因其较大的几何尺寸会减小襟翼缝道的面积使得襟翼缝道射流加速,有利于吹走襟翼表面的物面分离。

Study on Influence of Complex Geometry Details on the Aerodynamic Performance of High-lift System

By numerical simulation,the influence of the main-wing root geometry details,wing-mounted engine nacelle,slat tracks and flap track fairings on the aerodynamic performance of a high-lift system is investigated.The results show that a separated low-power vortex is generated by the wing-root fairing which is left at the main-wing root when the slat is cut,and the aerodynamic performance of the lift system is damaged seriously by this vortex.Cutting most of the wing-root fairing as part of the slat can eliminate the condition needed to generate the separated low-power vortex.Remarkable decrease of the stall angle and maxim lift coefficient is caused by a large size wing-mounted engine nacelle.This is mainly because of the flow mechanism that a large space filled with low-speed fluid above the upper surface of the main wing is generated by the separated fluid which comes from the nacelle upper surface,pylon and the gaps between the pylon and slat.Strong vortices generated by the nacelle strake with proper shape and setting at proper positions can eliminate most of the low-speed fluid and recover part of the aerodynamic performance loss.Low-momentum wake flow generated by the slat tracks mixed with the boundary layer of the main wing causes the loss of the lift.Large fluid separation may be caused by the slat track at high angles of attack,which will result in a remarkable loss of the aerodynamic performance.The flap slot section area may be diminished as a result of the blockage effect of the large size geometry the of flap track fairings,which may cause the high speed flow of the flap slot to move faster,thus blowing away the separation flow on the flap surface.