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一体化红外抑制器后机身狭缝进口布置对气流组织和红外辐射特性的影响
引用本文:杨宗耀,张靖周,单勇.一体化红外抑制器后机身狭缝进口布置对气流组织和红外辐射特性的影响[J].航空学报,2021,42(7):124445-124445.
作者姓名:杨宗耀  张靖周  单勇
作者单位:南京航空航天大学 能源与动力学院 江苏省航空动力系统重点实验室, 南京 210016
基金项目:国家科技重大专项(J2019-Ⅲ-0009-0053)
摘    要:针对一体化红外抑制器后机身顶部狭缝进气口布局的精细化设计需求,提出了改变进气狭缝位置以及面积的4个方案,基于旋翼下洗气流和尾桨气流的简化模型进行了后机身内外流耦合流动传热数值研究,并运用正反射线追踪法计算得到了后机身3~5 μm波段和8~14 μm波段的红外辐射强度空间分布,通过对比分析了狭缝进气口布局对一体化红外抑制器后机身气流组织和红外辐射特性的影响。结果表明:旋翼下洗气流对于机身两侧排出的热喷流掺混作用有所差异,存在尾桨气流时排气热喷流对喷口附近机身壁面的局部加热效应更显著;后机身顶部进气位置影响旋翼下洗气流的进气流量以及机身内部气流流动,进气口布置在后机身顶部外侧不利于旋翼下洗气流的导入,而进气口布置在后机身顶部内侧则导致旋翼下洗气流在混合管与机身壁面之间的局部流动较弱,使得该区域的气流温度较高;进气口面积增大虽有利于减小表面局部热点区域,却导致后机身上方的红外辐射强度有较大的增强。因此,进气口的位置和面积是重要的设计参数,合理的后机身内部气流组织可以提供有效的混合管冷却和后机身壁面热防护,改善3~5 μm波段和8~14 μm波段的红外辐射强度空间分布。

关 键 词:直升机  一体化红外抑制器  后机身  顶部进气口  气流组织  红外辐射  
收稿时间:2020-06-23
修稿时间:2020-08-18

Effects of slot-inlet arrangement at infrared-suppressor-integrated rear airframe on flow organization and infrared radiation characteristics
YANG Zongyao,ZHANG Jingzhou,SHAN Yong.Effects of slot-inlet arrangement at infrared-suppressor-integrated rear airframe on flow organization and infrared radiation characteristics[J].Acta Aeronautica et Astronautica Sinica,2021,42(7):124445-124445.
Authors:YANG Zongyao  ZHANG Jingzhou  SHAN Yong
Institution:Jiangsu Province Key Laboratory of Aerospace Power System, College of Energy and Power Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
Abstract:To meet the detailed slot-inlet-layout design requirement for the top-surface of an infrared-suppressor-integrated rear airframe, we propose four schemes by changing the slot-inlet locations and areas. Based on the simplified main-rotor downwash and tail-rotor flow models, numerical simulations are performed regarding the conjugated flow and heat transfer around the rear airframe. A forward-backward ray-tracing method is used to calculate the infrared radiation spatial-distribution in 3-5 μm and 8-14 μm bands. The current study illustrates preliminarily the effects of slot-inlet layouts on the internal flow organization and infrared radiation characteristics of an infrared-suppressor-integrated rear airframe. The results show that the impact roles of the main-rotor downwash on the exhaust plumes are distinct on both sides of the rear airframe. The presence of the tail-rotor flow aggravates the local heating effect of the exhaust flow on the exhaust-outlet nearby the rear airframe. The slot-inlet position affects the through-flow mass flow rate of the rotor downwash entering the rear airframe and the internal flow fields inside the rear airframe. When the slot-inlet is located far away from the central plane of the rear airframe, the through-flow mass flow rate is relatively smaller. However, when the slot-inlet is located near the central plane of the rear airframe, the flow in the local space between the mixing duct and the rear airframe wall is seriously weakened, leading to a local high-temperature zone. Enlarging the slot-inlet area helps to reduce the hot spots at the rear airframe, yet leads to an obvious increase of the infrared radiation emitting in the top direction. Therefore, the location and the area of the slot-inlet are identified as important geometric parameters affecting the internal flow organization and infrared radiation characteristics of an infrared-suppressor-integrated rear airframe. A proper internal flow organization could provide a more efficient cooling on the mixing duct and thermal protection on the rear airframe surface, improving the infrared radiation spatial-distribution in 3-5 μm and 8-14 μm bands.
Keywords:helicopters  integrated infrared suppressors  rear airframe  top-surface inlet  flow organization  infrared radiation  
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