高空离轨发动机流场红外辐射特性研究

Infrared radiation characteristics of high-altitude off-orbit engine plume

高超声速飞行器大攻角机动时,其离轨发动机产生的喷流与高速稀薄的大气来流产生强烈干扰,流场情况复杂,流场红外辐射也是天基红外系统探测的标志性事件。本文针对高超声速飞行器发动机喷流与稀薄来流的相互干扰情况,采用数值求解Navier-Stokes方程模拟干扰流场,采用逐线积分法得到气体红外辐射特性,结合反向蒙特卡洛方法计算得到飞行器在94公里飞行高度下,无来流、不同来流攻角、不同来流速度下的尾焰流场红外辐射特性,并针对低轨卫星的可观测性进行了评估。仿真结果表明,对于给定观测位置,在无风条件下,红外辐射在各个波段下的强度较低,最大值在10^(−9) W/m^(2)量级。而在来流攻角影响下,流场红外信号强度显著上升,且来流攻角、来流速度越大,强度越大,最大值在10^(−6) W/m^(2)量级。大气衰减效应对不同观测位置的可观测性影响较大。本文结果可为高超声速飞行器红外预警和反导提供参考。

When a hypersonic vehicle maneuvers at a high angle of attack,the jet generated by its off-orbit engine interferes strongly with the high-speed thin atmospheric flow,and the flow field is complicated,and the infrared radiation generated by the flow field is also a landmark event in space-based infrared system detection.In this paper,aiming at interference situation of the jet flow of hypersonic flight vehicle engine and thin flow,Navier-Stokes equations are numerically solved to simulate the interference flow field,and the infrared radiation characteristics of gas are obtained by the line-by-line integration method.Combining with the backward Monte Carlo method,the infrared radiation characteristic of exhaust plume are obtained when the aircraft flight′s altitude is 94 kilometers,with no wind,different incoming flow attack angles and different ve-locities are considered,and the observability of low orbit satellites is evaluated.The simulation results show that for a given observation position,the intensity of infrared radiation in each band is low when there is no wind,and the maximum value is 10^(−9) W/m^(2).Under the influence of incoming flow attack angles,the infrared signal intensity of the flow field increases significantly with greater attack angle and velocities and the maximum value reaches 10^(−6) W/m^(2).The atmospheric attenuation effect has great influence on the observability of different observation positions.The results can provide reference for infrared warning and anti-missile of hypersonic vehicle.