大型飞机扁平后体导流片减阻增稳研究

Research on chine of aerotransport after-body for drag reduction and stability enhancement

运输机采用扁平后体的设计形式可使舱门结构简单、重量轻,并且舱门机构的可靠性高,具有很好的使用性。但是扁平后体在巡航时横向流动比较严重,造成横向逆压梯度大且后体边界层易出现分离形成旋涡流动,带来压差阻力的增加。并且,后体分离涡在偏航时使垂尾两侧压力分布变差,降低了航向稳定性。导流片是特别针对扁平后体所采用的特殊气动力部件。其能够对后体涡的生成和发展进行抑制,削弱后体低压区,降低压差阻力;在偏航状态下,导流片改变了垂尾和后体的压力分布形态,可有效增加航向稳定性。导流片的减阻增稳作用使得采用扁平后体的运输机装载效率和气动特性得以兼顾。

With flat after-body, large cargo aircraft have simpler structures, less weight, and the port machine has high dependability. However, the flat after-body induces strong transverse flow and flow with high adverse gradient when the aircraft cruises, so the boundary layer on the after-body is easier to separate. Separated flow increases pressure drag, and the separated vortex worsen the pressure distributions on the both side of vertical tail when the aircraft yaws. So the yawing stability is reduced. The chine is a special aerodynamic device which is used on flat after-body. It can restrain the birth and development of vortex flow. When the aircraft yaws, the chine can also enhance yawing stability by improving pressure distributions on the surfaces of vertical tail and after-body. Because of the functions of drag reduction and stability enhancement, the chine makes the transport aircraft with flat after-body having both high load efficiency and satisfied aerodynamic performance.