小偏距S弯二元喷管的红外辐射特性数值分析

为了降低飞行器的红外辐射,适应发动机排气系统与飞机后机身的匹配,设计了一种非常规的S弯二元喷管,喷管出口中心线与发动机轴线不共线,有一个小偏距.在商业软件中计算该S弯二元喷管的温度场、速度场、压力场和组分浓度的分布,采用自主开发的红外软件,用反向蒙特卡罗法计算该喷管的红外辐射特性,并与基准轴对称喷管的计算结果进行对比,计算结果表明:采用小偏距S弯二元喷管后,能够对排气系统内部高温部件有一定的遮挡,对红外辐射特征有一定的抑制作用,最大能够降低33%的红外辐射. 

Numerical analysis on infrared radiation characteristics of two-dimensional S-nozzle with small offset

In order to reduce the infrared radiation of aircraft, and make the exhaust system match the aircraft afterbody, a kind of unconventional two-dimensional(2-D)S-nozzle was designed to suppress the infrared radiation characteristics. There was a small offset given that the nozzle's center line and the engine's axis were not collinear. Based on the distribution of temperature, pressure and species mass fraction of the two-dimensional S-nozzle obtained from CFD results, the infrared radiation characteristics of two-dimensional S-nozzle was calculated with reverse Monte-Carlo method, then analyzed and compared with axisymmetric nozzle. The results show that, the two-dimensional S-nozzle is capable of shielding the high temperature elements inside the exhaust system effectively, and the infrared radiation characteristics of the exhaust system can be further suppressed by 33%.