%0 Journal Article
%T 发动机位置对大型运输机动力增升效能的影响研究<br>Numerical Investigation of the Influence of Engine Positions on Powered High-Lift Effects for Large Transport Aircraft
%A 龚志斌
%A 李杰
%A 蒋胜矩
%A 张恒
%J 西北工业大学学报
%D 2015
%X 参照C-17运输机,建立了外吹式襟翼动力增升全机几何分析模型。采用多块结构化网格技术,基于RANS方法,分别对高升力构型和轴对称发动机动力喷流进行了数值模拟验证,在此基础上开展了发动机短舱位置和喷流方位对动力增升效能的影响研究并总结其设计原则。计算结果表明,短舱垂直位置对动力增升效能影响最为显著,发动机每下沉100 mm升力至少损失0.1。为获得理想的动力增升效果,发动机短舱应在避免巡航状态喷流直接冲刷机翼下表面的前提下尽可能地靠近机翼。发动机水平位置主要影响中等以上迎角的气动力特性,短舱前伸有利于喷流进入缝道并且存在兼顾最大升力系数和失速和缓特性的最佳前伸量。发动机负的安装角每增加1°,升力可增加0.1以上,适当给定负的发动机安装角可使得尾喷流向上倾斜从而被襟翼完全阻挡。通过改变发动机位置,在起到更好的动力增升效果的同时,通常都伴有低头力矩增大,压力中心后移,以至于全机安定性增加的同时平尾配平的负担也相应增加。<br>Taking C-17 transport as reference, we construct powered high-lift transport configuration with externally blowing flap (EBF). Based upon multi-block structured grid techniques and RANS methods, numerical validations are carried out on a high-lift model as well as an axisymmetric fan-jet engine model. Then the influences of engine positions on powered high-lift efficiency are investigated and the design rules for engine positions are summarized. Results and their analysis show preliminarily that the vertical positions of the engines are the primary factors for high-lift. For every 100mm drop of nacelles, the lift coefficients will reduce more than 0.1. The nacelles should be installed as close as possible to the wing to obtain ideal high lift while making sure that the jet flow does not impinge directly on lower wing surfaces at high speed cruise conditions. The horizontal positions of the nacelles mainly affect the aerodynamics above medium flow angle. The jet flow can get through the flap slots more easily with the engines placed more forward and the optimum horizontal positions exit considering both the maximum lift and stall properties. The lift coefficients will increase above 0.1 for every 1 degree increase of the negative nacelle installation angle. Moderate negative engine installation angle contributes to the powered high-lift effects by making the jet flow deflect upward and be totally blocked by the flaps. When changing the engine positions for better high-lift effects, the pitching moment will always be larger, which means that the aerodynamic center will move backward and longitude trim and stability problems may be severer
%K 外吹式襟翼
%K 动力增升
%K 多块结构化网格
%K 雷诺平均N-S方法
%K 发动机位置&lt
%K br&gt
%K aerodynamic stalling
%K aircraft engines
%K angle of attack
%K boundary conditions
%K computer simulation
%K control surfaces
%K design
%K efficiency
%K flow rate
%K geometry
%K installation
%K lift
%K Mach number
%K mathematical models
%K mesh generation
%K Navier Stokes equations
%K Reynolds number
%K stability
%K transport aircraft
%K turbulence models
%K VTOL/STOL aircraft
%K wings
%K engine positions
%K externally blowing flap(EBF)
%K multi-block structured grid
%K powered high-lift
%K RANS methods
%U http://journals.nwpu.edu.cn/xbgydxxb/CN/abstract/abstract6413.shtml