进排气对尾吊短舱布局飞机气动特性影响研究

Influence of intake and exhaust on aerodynamic characteristics of tail suspended nacelle aircraft

在尾吊短舱式布局飞机设计中,发动机进排气对其他部件的气动影响是需要关注的重要问题,为了全面研究发动机进气与喷流对全机气动特性的影响,在某尾吊舱短舱布局飞机巡航条件下(H=11000m、Ma=0.78)对流场开展了数值仿真研究,重点分析了短舱通气模型与带进排气模型的全机升阻力特性及流场分布情况。计算结果表明:采用近距尾吊短舱布局的飞机,发动机进排气对全机气动特性的影响主要体现在短舱与机翼的气动干扰方面,在所研究的迎角范围内(-2°~8°),发动机进气所带来的抽吸作用改变了机翼及短舱表面的压力分布,使得机翼上表面的负压区面积增大、短舱上唇口激波强度减弱,导致全机升力系数增加、阻力系数减小、升阻比提高,但这一气动特性的改善趋势随着迎角的增大而逐渐减缓。

In the design of tail suspended nacelle aircraft,the aerodynamic effects of engine intake and exhaust on other components need to be paid attention to.In order to comprehensively study the influence of engine intake and jet flow on the aerodynamic characteristics of the whole aircraft,the numerical simulation of the flow field was carried out under the condition of a tail suspended nacelle aircraft cruise(H=11000 m,Ma=0.78),focusing on the comparative analysis of lift and drag characteristics and flow field distribution between the nacelle ventilation model and with intake and exhaust model.The calculation results show that,the influence of engine intake and exhaust on the aerodynamic characteristics of the aircraft with close tail suspended nacelle is mainly reflected in the aerodynamic interference between nacelle and wing.In the studied angle of attack range(-2°~8°),the suction effect caused by the engine intake changes the pressure distribution on the surface of the wing and nacelle,increaseing the aera of the negative pressure zone on the upper surface of the wing.The strength of the shock intensity of the upper lip of the nacelle decreases,which makes the lift coefficient increase,the drag coefficient decrease and the lift-drag ratio increase.However,the improvement trend of the aerodynamic characteristics gradually slows down with the increase of the angle of attack.