一体化红外抑制器排气出流对其气动和红外辐射特性的影响  

Effects of infrared-suppressor-integrated exhaust outflow on its aerodynamic and infrared radiation characteristics

作　　者：文星耀 张靖周[1] 单勇[1] Wen Xingyao;Zhang Jingzhou;Shan Yong(Key Laboratory of Thermal Management and Energy Utilization of Aircraft,Ministry of Industry and Information Technology,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,航空飞行器热管理与能量利用工业和信息化部重点实验室,江苏南京210016

出　　处：《红外与激光工程》2024年第1期68-82,共15页Infrared and Laser Engineering

摘　　要：经地面模型实验验证,数值仿真展示了一体化红外抑制器排气出流、模拟旋翼下洗气流和模拟前飞来流相互作用下的流动和换热特征,通过改变排气出流角度和模拟前飞来流速度,计算分析一体化红外抑制器引射、混合特性以及红外辐射强度空间分布的变化规律。仿真结果表明:模拟的前飞来流与排气出流相互作用后会造成局部排气不畅,前飞来流甚至倒灌入红外抑制器内,从而引起抑制器壁面局部高温,增加了抑制器整体红外辐射强度;改变排气角度可将之改善,且存在气动和红外辐射特性兼顾的最佳角度。前飞来流速度从15 m/s提高到55 m/s,抑制器内部高温壁面温度降低,抑制器红外辐射强度峰值在3~5μm波段降低约50%,在8~14μm波段降低约20%。红外抑制器的下洗气流进口加装弯曲导流片可以对内部混合管高温壁面进行遮挡,有效降低顶部视角的红外辐射强度。最佳排气角度下,利用排气下游隔板的遮挡,正对抑制器排气出口方向(底部视角)上的3~5μm和8~14μm波段红外辐射峰值分别降低约50%和33%。Objective The armed helicopter is in the blind area of radar detection when performing low-altitude missions,but more attention should be paid to the threat of infrared guided weapons.Integrated into the rear fuselage of the helicopter,the infrared suppressor offers excellent stealth capabilities due to its small spatial footprint and the ability of rapid mixing and cooling at short distances.Over the past decades,significant progress has been made in understanding the mechanisms of infrared suppression,enhancing the performance of the suppressor in the areas such as cold-air injection,cold-hot flow mixing,and obscuration of high-temperature components.However,the infrared stealth effectiveness of the suppressor from the top and bottom perspectives has always been suboptimal,necessitating the search for optimal suppressor structures for further improvement.Furthermore,during the helicopter cruising,the suppressor exhaust is inevitably affected by the forward flow.Therefore,it is essential to study the performance of the infrared suppressor under the coupled conditions of forward flow,thermal exhaust,and rotor downwash.Methods In this study,an integrated physical model of the infrared suppressor is constructed,which includes the outer skin and the exhaust system(Fig.1).On the basis of the verification of ground model experiment,the simulation of forward flow and variations in the exhaust flow angle are added to assess how these changes affect the flow dynamics,heat transfer,and spatial distribution of infrared radiation intensity within the suppressor.The infrared radiation intensity was calculated using forward-backward ray-tracing method.Results and Discussions The results of ground experimental measurement and simulation calculation meet the error requirements,proving the calculation method in this paper is feasible.The increase of the forward flow velocity will increase the ejection coefficient of the lobed nozzle(Fig.10),but will reduce the total pressure recovery coefficient of the exhaust system(Fig.12),and

关 键 词：红外抑制器 波瓣喷管 总压恢复系数 红外辐射 引射系数 旋翼下洗 

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]