航空发动机排气系统雷达散射特性数值计算

Numerical Study on Radar Scattering Characteristics of Aeroengine Exhaust System

为了获取航空发动机排气系统的雷达散射特性,以亚巡状态典型发动机排气系统物理模型为基础,采用高频计算方法弹跳射线法计算了排气系统在6、10、15 GHz 3个典型频点下水平极化与垂直极化的雷达散射截面(RCS)分布规律,并通过计算10GHz频点的热点成像确定了排气系统中的强散射源。结果表明:随着频率的提高,雷达波对目标细节的探测能力有所增强,排气系统RCS曲线上的强散射峰值数量明显增加,且分布位置有所不同;随着俯仰角的增大,排气系统在水平探测面-30°~30°内的RCS散射峰值的分布位置与强度均发生变化,与俯仰角0°时相比,RCS均值最大降幅可达94.1%;综合不同探测角度下的成像情况,支板、加力内锥、火焰稳定器与喉道截面热点强度较大,是雷达波的强散射源,也是发动机雷达隐身需要关注的重点。

To obtain radar scattering characteristics of an aeroengine exhaust system,the exhaust system model was established and the high-frequency shooting and bouncing ray calculation method was used to calculate the horizontal and vertical polarization of radar cross section(RCS) distribution of the exhaust system at three typical frequencies of 6 GHz,10 GHz,15 GHz. Through the analysis of the hot spot distribution of the exhaust system at 10 GHz,the strong scattering sources in the exhaust system were determined. The results show that with the increase of frequency,the detection ability of radar waves to target details is enhanced,and the number of strong scattering peaks on the RCS curve of the exhaust system is significantly increased,with different distribution positions. The distribution position and intensity of the RCS scattering peaks of the exhaust system in the range of -30° to 30° at horizontal detection plane vary with the increase of the pitch angle,the maximum decrease of RCS average value can reach 94.1% compared with the pitch angle of 0 °;Considering the results at different detection angles,struts,exhaust cone,flame holders and nozzle throat are components with high intensities,which are the strong scattering sources of radar waves and the focus of the engine design for radar stealth.