航空发动机排气喷管红外辐射特征数值研究

红外隐身技术对提高未来战机战场生存力具有重要意义,发动机排气系统是飞机后半球的主要红外辐射源。为了研究涡扇发动机排气喷管的红外辐射特性,采用与成熟商用CFD软件相结合的策略,基于离散传递方法,自主开发航空发动机排气系统红外辐射特征数值计算软件。提出一种射线行程追踪方法,用来提高软件计算效率和模拟精度;最后用该软件对某型涡扇发动机排气系统收缩喷管及两种采用不同红外抑制措施的喷管进行数值模拟研究。结果表明：相对于传统的收缩喷管,二元喷管能够在绝大部分探测方向上有效降低喷管的红外辐射,引射喷管可在大角度探测方向上起到显著的红外隐身效果。

Numerical simulation of infrared characteristics of aero-engine exhaust nozzle

Infrared stealth is of great importance to increase the survival ability of the future aircraft. The exhaust system of the engine is the main source of infrared radiation at the tail hemisphere of the aircraft. In order to investigate the infrared radiation characteristics of the turbofan engines nozzle, a software for calculating the infrared radiation characteristics of the aero-engine exhaust system based on the discrete transfer method of infrared radiation numerical computation is developed, combining with mature CFD software. A ray-tracing method is proposed to improve the efficiency and precision of the calculation. Finally, the simulation of a baseline turbofan convergent nozzle and two improved nozzles with different infrared suppression measures is performed with the software. The results show that 2D nozzle can dramatically suppress infrared radiation of the nozzle in most orientation of detection while the infrared radiate intensity of ejector nozzle is less than the convergent nozzle at high azimuth angles and ray-tracing method is efficient and precise. The software developed can provide assistance for the design of exhaust nozzle with low infrared signal.