Numerical and experimental investigation of infrared radiation characteristics of a turbofan engine exhaust system with film cooling central body
Numerical and experimental investigation of infrared radiation characteristics of a turbofan engine exhaust system with film cooling central body
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DOI：
10.1016/j.ast.2012.11.008
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发表时间：
2013-07
影响因子：
5.6
通讯作者：
Yong Shan;Jing-zhou Zhang;Cheng-xiong Pan
中科院分区：
文献类型：
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作者：
Yong Shan;Jing-zhou Zhang;Cheng-xiong Pan
针对涡扇发动机排气系统的红外辐射问题，提出了一种新型的气膜冷却中心体概念。通过实验和数值计算对红外抑制能力进行了评估。实验结果验证了采用前后向射线追踪和窄带模型的数值计算方法的正确性。针对几种不同的排气系统结构，研究了有、无气膜冷却中心体排气系统的气动特性和红外辐射分布。实验结果表明，旁通流可以起到冷却中心体和抑制发动机尾部红外辐射的作用。旁路通道中凸耳的入口面积决定了进入中心体的质量流率。为了获得气膜孔结构对排气系统表面温度和红外辐射强度的影响，对全尺寸排气系统进行了一系列计算。数值模拟结果表明，在零角度（垂直于喷管出口方向），气膜冷却中心体比无气膜冷却中心体可抑制内包层红外辐射40-70%。涡扇发动机排气系统气膜冷却中心体具有显著的抑制喷管内壁面红外辐射的能力。
A new concept of film cooling central body for the exhaust system of turbofan engine was brought out to suppress the infrared radiation of engine in this paper. The ability of infrared suppression was estimated by experiments and numerical calculations. The numerical method, which use forward–backward ray tracing and narrow band model, had been validated by the experimental results. The aerodynamic characteristics and infrared radiation distribution of exhaust system with/without film cooling central body were investigated for several different configurations. The experimental results reveal that the bypass flow can be used to cooling the central body and suppress the infrared radiation at the rear aspect of the engine. The inlet area of lugs in the bypass passage determined the mass flow rate into the central body. To obtain the effects of the film cooling holes configuration on the surface temperature and infrared radiation intensity of the exhaust system, a series of computations on full scale exhaust system have been performed. The numerical simulation results indicate that the film cooling central body can suppress the infrared radiation of the inside enclosure by 40–70% comparing to the central body without the film cooling at zero degree aspect (normal to nozzle outlet). The film cooling central body for exhaust system of turbofan engine has remarkable ability to suppress the infrared radiation from the inside enclosure of nozzle.