涡扇发动机引射喷管的红外辐射特性数值研究

Numerical Simulation on the Infrared Radiation Characteristics of Turbofan Engine's Ejector Nozzle

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引射喷管的红外辐射特性,结合引射喷管的CFD计算,采用离散传递法计算红外辐射强度,研究了普通引射喷管以及带5°下倾角的引射喷管后半球3～5μm以及8～14μm波段的红外辐射强度空间分布规律,并与相似尺寸的涡扇/涡喷发动机收缩喷管进行比较。结果表明:在探测角度较大时,涡扇发动机引射喷管的红外辐射强度较收缩喷管小20%左右;引射喷管结构上的非对称性导致红外辐射强度角向分布也呈现非对称性特征;8～14μm波段与3～5μm波段的红外辐射空间分布规律基本相同,但辐射能量小40%左右。

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 engine＇s ejector nozzle,combining the flow field calculation,using the discrete transfer method of infrared radiation numerical computation,the infrared radiation field characteristic of normal turbofan engine＇s ejector nozzle and the ejector nozzle with 5° install angle in the waveband of 3～5 μm and 8～14 μm at the tail hemisphere is researched,and compared with the turbofan/turbojet engine＇s convergent nozzle.The results show that the infrared radiate intensity of turbofan engine＇s ejector nozzle is 20% less than the convergent nozzle at high azimuth angles and the symmetry radiation field distribution of the nozzles are changed by the install angle obviously.The radiation field distribution in the waveband of 8～14 μm is the same as that of 3～5 μm,but the radiant energy is 40% less than that of 3～5 μm.