翼吊长涵道发动机短舱内偏角优化和机理研究

Aerodynamic optimization of under-wing nacelle toe-in angle and mechanism analysis

翼吊式发动机短舱是现代大中型飞机最常采用的气动布局形式,发动机短舱及挂架相对于机翼的展向位置、弦向位置、垂向位置、内偏角、安装角均会对它们之间的流场产生影响,进而影响全机的气动特性。本文采用CFD数值计算的方法,对翼吊长涵道发动机短舱的内偏角进行优化分析。对比分析了不同内偏角时,高速巡航状态的干扰阻力和低速大迎角状态的失速特性,研究了高速巡航时挂架内侧出现高负压峰值的机理,以及不同剖面形状的挂架对内偏角优化的影响。计算结果表明:内偏角-0.5°、0°和0.5°时,干扰阻力及升力损失较小,不同剖面形状的挂架不会对内偏角优化结果产生较大影响,但可以减小挂架内侧的负压峰值。本文得出的结论对工程上翼下吊挂外挂物有一定的指导意义。

Under-wing engine nacelle is most commonly used aerodynamic layout of modern large and medium-sized aircraft.The spanwise position,chord position,vertical position,toe-in angle and installation angle of the engine nacelle-pylon relative to the wing will affect the flow field between them,then the aerodynamic characteristics of the whole aircraft are affected.The CFD numerical calculation method is used to optimize toe-in angle of under-wing nacelle and its pylon.We compared the interference resistance of high-speed cruise and stall characteristics of low-speed high angle of attack,researched the mechanism of negative pressure peak on the inside of the pylon,and influence of pylon with different section shapes on toe-in angle.The calculated results show the interference resistance and lift loss are small when the internal deflection angle is at-0.5°,0°and 0.5°respectively,and the pylon with different profile shapes will not have great influence on the optimization results of internal deflection angle,but can reduce the negative pressure peak value inside the pylon.The conclusion in this paper has some guiding significance for hanging the external store under the upper wing.