Simulation Of Infrared Detection And Imaging Of High-speed Aircraft In Complex Atmosphere

The use of high-speed aircraft plays an important role in modern warfare and has a major impact on national security and the world pattern.With the development of engine technology,the flying speed of the aircraft can reach more than 5Ma,which is difficult to be detected by radars.However,when flying at a high speed,the friction between the aircraft's skin and the atmosphere will generate a lot of aerodynamic heat,which will increase the temperature of the skin and the surrounding air,and produce a lot of infrared radiation.Due to the existence of interference sources such as aerosols and atmospheric turbulence in the atmosphere,the transmission of infrared radiation in the atmosphere is interfered,which affects the detection of the high-speed aircraft.Therefore,it is necessary to study the infrared detection of high-speed aircraft in complex atmosphere.In this paper,the numerical simulation of the flow field of high-speed aircraft is carried out,the characteristics of complex atmospheric medium are analyzed,and the infrared images of high-speed aircraft in complex atmosphere are simulated.The main contents are as follows:First,using the CFD software Fluent to solve the flow field of a high-speed aircraft,and comparing with the NASA-TN-D5450 wind tunnel test to verify the reliability of the calculation method,the temperature distribution and pressure distribution of the highspeed aircraft flow field in different conditions are obtained.Second,the influence mechanism of atmospheric turbulence on radiation transmission is analyzed,and the calculation model of the turbulent atmospheric refractive index field is established.The standard atmospheric refractive index is calculated based on the modified Edlen atmospheric refractive index empirical formula.According to the atmospheric refractive index structure constant and atmospheric turbulent power spectral the turbulent pulsating refractive index field is solved,and refractive index fields of turbulent atmosphere in different atmospheric scenes are established.Also,according to the physical property data and spectral distribution data of different types of aerosols,the radiation characteristics of typical aerosol particles were calculated.Compared with the results in the literature,the correctness of the program was verified.And the radiation characteristics of aerosol particle system are calculated according to the radiation characteristics of sparse particle system.Third,Reverse Monte Carlo Method was used to simulate infrared images of high-speed aircraft in complex atmospheric,and the effects of atmospheric turbulence and aerosols on infrared detection were analyzed.The research results of this paper have certain reference value for infrared detection in complex atmospheric,and have important theoretical significance and application value for the detection,identification and early warning technology of high-speed aircraft.