翼面形状对翼伞气动性能的影响

Planform Geometry Effect on Aerodynamic Performance of Parafoils

为了研究不同翼面形状对翼伞气动性能的影响,文章以某型冲压翼型为对象,建立了翼伞滑翔阶段稳态绕流流场数值模型,分析了翼面后缘形状对稳态滑翔阶段翼伞流场结构及气动特性的影响,在此基础上探究了后缘前掠角大小对翼伞气动性能的影响。研究结果表明,后缘前掠型翼面的上翼面前缘压力降低,有利于减小翼面压差阻力,升阻性能最好,翼伞设计时宜采用后缘前掠型翼面设计;随着前掠角增大,升力系数和阻力系数均先减小后增加,翼伞升阻比随着前掠角增大呈现先增后减的趋势;当前掠角过大时,上翼面流动分离区变大,压差阻力增加会导致升阻比降低;综合流场结构和气动特性考虑,前掠角为6°时翼伞气动性能最优。研究成果可为高滑翔翼伞设计提供一定参考。

To study the aerodynamic performance of the parafoils with different platform geometries,this paper establishes numerical model of steady flow around parafoils during its glide phase.The influence of the trailing edge shape of parafoil on the flow field structure and aerodynamic characteristics under steady descent is analyzed,and the influence of the trailing edge swept forward angle on the aerodynamic performance is investigated on the basis of this study.The results reveal the following conclusions:the swept-forward parafoil has a reduced pressure at the leading edge of the upper surface,which is conducive to the reduction of drag coefficient due to pressure difference and the best aerodynamic performance,so that trailing edge with forward-swept shape is preferred for parafoil design.With the increase of swept angle,both the lift and drag coefficient decrease first and then increases,and the lift drag ratio increases first and then decreases.The flow separation increases with the swept angle,which leads to increased drag due to pressure difference,as a result,the lift drag ratio decreases.Considering the flow field structure and aerodynamic characteristics,the forward-swept platform shape with swept angle 6°can improve the aerodynamic performance best.This paper can provide some reference for the design of high gliding parafoils.