BLI效应下整流罩设计对翼型气动特性的影响

Effects of cowling design on aerodynamic performance of airfoil with BLI

边界层吸入(BLI)效应对飞行器气动特性的影响比较显著,而整流罩的设计会进一步影响BLI效应下的翼型气动特性。为了揭示BLI效应下整流罩的主要设计参数对翼型气动特性的影响及其原因,本文采用计算流体力学(CFD)和Morris敏感度分析相结合的方法对该问题进行了详细研究,得到了整流罩主要设计参数对翼型气动特性的敏感度排序和耦合影响程度排序;对敏感度较高和耦合影响较大的参数进行了流动分析。结果表明:在巡航和起飞2种状态下,对气动系数影响相对较大的设计参数是整流罩最大厚度和进气边界弦向位置,整流罩最大厚度对翼型气动特性影响的主要原因是整流罩背风面会发生局部分离,且其还会改变阻力-流量系数曲线的趋势;整流罩最大厚度和进气边界弦向位置对翼型气动特性的耦合影响作用较强。

Boundary layer ingestion（ BLI） effect significantly influences aircraft aerodynamic performance. Cowling design further affects aerodynamic performance of airfoil with BLI effect. To clarify the effect and its reason of main cowling design parameters on aerodynamic performance of an airfoil with BLI effect,a detailed study was investigated by computational fluid dynamics（ CFD） method and Morris sensitivity analysis method. Sensitivity order and coupled effect order of main parameters on aerodynamic performance were obtained. Flow details of parameters with higher sensitivity and greater coupled effect were analyzed. The results show that in cruise and take-off conditions,the parameters with relatively great impact are cowling maximum thickness and inlet location along the chord direction. The main reason of effects of cowling maximum thickness on aerodynamic performance is that local stall occurs at cowling surface. The variation of cowling maximum thickness also affects the variation trend of plot of drag coefficient to mass flow rate. The coupled effect of cowling maximum thickness and inlet location along the chord direction on aerodynamic performance is relatively great.