中心锥冷却结构对航空发动机红外辐射特性影响的数值研究

Numerical Investigation of effect of central cone cooling structure on the infrared radiation characteristics of aero-engine exhaust system

为研究航空发动机中心锥冷却结构对红外辐射特性的影响,采用逆向蒙特卡洛法,计算了1个典型加力式涡扇发动机收扩喷管的红外辐射特性,并对比分析了在中心锥外层与开孔之间增加1个盖板(A型)和不加盖板(B型)两种中心锥冷却结构的红外抑制效果。研究结果表明:在正后方附近的探测方位上,收扩喷管的红外辐射贡献主要来自中心锥的高温固体壁面,有必要采取抑制措施降低其表面温度;A型和B型两种中心锥冷却结构均可有效抑制中心锥部件的固体辐射;在不改变中心锥表面发射率的情况下,具有A型中心锥冷却结构的收扩喷管的辐射强度最大降低了9.10%,具有B型中心锥冷却结构的收扩喷管最大降低了16.98%。所得结论具有较高的工程应用价值,可为发动机红外隐身设计提供参考。

In order to study the influence of the central cone cooling structure on the infrared radiation characteristics of aero-engine,the infrared radiation characteristics of a typical augmented turbofan convergent/divergent nozzle were calculated by using Reverse Monte Carlo Method(RMCM),and the infrared suppression effects of two central cone cooling structures with a cover plate(A-type central cone)and without a cover plate(B-type central cone)were compared and analyzed.The results show that the infrared radiation contribution of the nozzle is mainly from the high temperature solid wall of the central cone,and it is necessary to reduce the surface temperature of the nozzle.Both A-type and B-type cooling structures can effectively inhibit the solid radiation of the central cone components.Under the condition that the surface emissivity of the central cone is not changed,the radiation intensity of the adduction nozzle with A-type central cone cooling structure is reduced by 9.10%at most,and that of the adduction nozzle with B-type central cone cooling structure is reduced by 16.98%.The results have high engineering application value and can provide reference for the infrared stealth design of engine.