航空学报2025，Vol.46Issue(8)：144-161,18.DOI:10.7527/S1000-6893.2024.31139
气膜冷却矢量喷管冷却/气动/红外辐射特性
Film cooling performance/nozzle performance/infrared radiation characteristics of a vector nozzle
摘要
Abstract
To improve the performances of aero-engine nozzle in long service life and high infrared stealth,a detailed numerical analysis of the complex flow field in the divergent section of the vector nozzle is carried out.The interference between the secondary coolant and the main flow is firstly studied.Further,the influences of the complex flow field on the film cooling performance,the aerodynamic characteristics,and the intensity of the backward infrared radiation are analyzed.The results show that the secondary flow induces shock wave/expansion waves when injected into the su-personic mainstream.The complex waves further develop and impinge on the nozzle wall.Under constant main-stream and secondary coolant flow inlet conditions,the impingement locations of the complex waves move upstream with the increase of the vector angle.The film cooling efficiencies at the wave impingement locations decrease as the boundary layer rises.Additional pressure loss is induced when the mainstream flows through the complex waves,re-sulting in a decrease of the thrust coefficient and an increase of the total pressure loss,compared to the case without film cooling.The influence of the film injection position is considered.Compared to the downstream secondary flow in-jection,the upstream secondary flow injection leads to a lower film cooling efficiency,but a larger film coverage area.The effect of the number of coolant injection slots is also studied.With three slots,the average cooling efficiency on the upper and lower walls is 0.907 5 and 0.912 1,respectively,which increases by up to 92.55%and 98.37%,re-spectively,when compared to the condition with single slot.In contrast,the thrust coefficient and the total pressure re-covery coefficient decrease by up to 1.62%and 2.20%,respectively.Then,the cooling and thrust performances of the gas mainstream are compared with the air mainstream.Taking gas as the working fluid,the cooling efficiency along the fully developed section of the secondary flow is lower,but the nozzle thrust coefficient is higher.Finally,the nozzle backward infrared radiation,the brightness of which corresponds to the nozzle flow field is also studied.In the wave bands 1-3 μm,3-5 μm,and 8-14 μm,the injection of the secondary flow decreases the average radiation in-tensity by 67.39%,56.58%,and 56.68%in the pitch plane,and 26.77%,23.88%,and 23.24%in the yaw plane.The results of the study provide theoretical basis and basic database for the cooling designs of the vector nozzles.关键词
超声速喷管/矢量偏转/气膜冷却/冷却效率/气动特性/红外辐射特性Key words
supersonic nozzle/vector deflection/film cooling/cooling efficiency/aerodynamic characteristics/in-frared radiation characteristics分类
航空航天引用本文复制引用
陈玲玲,张杨,施永强,杨青真..气膜冷却矢量喷管冷却/气动/红外辐射特性[J].航空学报,2025,46(8):144-161,18.基金项目
国家自然科学基金(12102356) （12102356）
