带全遮挡导流支板排气系统流动传热及红外抑制效果数值分析  

Numerical analysis of flow and heat transfer in exhaust system with fully shielded guiding strut and infrared suppression effect

作　　者：朱友缘 陈铭 张海波[1] ZHU Youyuan;CHEN Ming;ZHANG Haibo(College of Energy and Power,Nanjing University of Aeronautics and Astronautics,Nanjing 210016,China)

机构地区：[1]南京航空航天大学能源与动力学院,江苏南京210016

出　　处：《推进技术》2024年第6期164-176,共13页Journal of Propulsion Technology

基　　金：国家科技重大专项(J2019-III-0009-0053)。

摘　　要：为了降低涡扇发动机末级涡轮的强红外辐射特征,设计了全遮挡导流支板(Fully Shielded Guiding Strut,FSGS)并进行了三种不同的红外抑制措施(低发射率材料、气膜冷却和综合抑制措施)研究,其中采用源项法对支板进行不同孔径下的气膜冷却仿真验证,得到了支板在采用气膜冷却后的红外辐射亮度图,揭示了各种抑制措施对气动及红外特性的影响规律,同时将本文方法与二元收扩(2D C-D)喷管进行对比分析了两者的优劣。结果表明:对支板单独采用低发射率材料时在0°观测方向排气系统积分红外辐射最大降低了35.38%;对支板单独采用气膜冷却可使支板表面温度明显降低,支板冷却效率为0.640时,在0°观测方向红外辐射强度降幅最大可达43.59%,且损失的气动性能较小;采用气膜冷却和低发射率材料综合抑制措施时,随着材料发射率的减小排气系统表征出的红外辐射强度反而增加。综合来看,气膜冷却在支板红外抑制时应优先考虑。同时二元喷管与本文方法各有利弊,在小角度和大角度下气膜冷却导流支板都能起到更好的抑制效果,但会损失更多的气动性能,同时结构更加复杂。In order to reduce the strong infrared radiation characteristics of the last stage turbine of the turbofan engine,a fully shielded guiding strut(FSGS)was designed,and three different infrared suppression measures(low emissivity materials,air film cooling,and comprehensive suppression measures)were studied.The source item method was used to simulate and verify the air film cooling of the strut under different aperture sizes,and the infrared radiation brightness map of the strut was obtained after adopting air film cooling,revealing the influence of various suppression measures on the aerodynamic and infrared characteristics.At the same time,the advantages and disadvantages of the proposed method and the 2D nozzle were compared and analyzed.The results show that when using low emissivity materials alone on the strut,the maximum integral infrared radiation in the exhaust system in the 0°observation direction can be reduced by 35.38%.When air film cooling is used alone on the strut,the surface temperature of the strut can be significantly reduced.When the cooling efficiency of the strut is 0.640,the maximum decrease in infrared radiation intensity in the 0°observation direction can reach 43.59%,with a smaller loss of aerodynamic performance.When using a comprehensive suppression measure of air film cooling and low emissivity materials,the infrared radiation intensity characterized by the exhaust system increases with the decrease of material emissivity.Overall,air film cooling should be given priority in infrared suppression of the guiding strut.At the same time,the two-dimensional nozzle and the method proposed in this article have their own advantages and disadvantages.The film cooling guiding strut can achieve better infrared suppression effect at both small and large angles,but it will lose more aerodynamic performance and have a more complex structure.

关 键 词：涡扇发动机 全遮挡导流支板 红外抑制 气膜冷却 二元喷管 

分 类 号：V231.1[航空宇航科学与技术—航空宇航推进理论与工程]