Infrared Image Simulation Of Aircraft Based On Ray Tracing

The infrared image simulation of aircraft targets has very important military and civilian significance.The traditional simulation method usually images the body of the aircraft target and the tail flame separately,so it rarely shows the coupling relationship between the two,and it is difficult to obtain a high-fidelity simulation image.In recent years,in the field of aircraft target infrared radiation research,the calculation of flow field using computational fluid dynamics has been a common method,mainly using flow field values for radiation calculation and radiation characteristics analysis.Based on this,this thesis will discuss how to use the value of the simulated flow field to obtain an infrared simulation image of the aircraft target with high realism and high precision.Firstly,according to the theory of infrared radiation transmission and ray tracing,the infrared radiation calculation is combined with the ray tracing method,and obtained the ray tracing rendering method which can be used for numerical simulation of infrared scene.The comparison with the real shot image verifies the credibility of the simulated image.Then,according to the theory of fluid mechanics and computational fluid dynamics,the geometric model of the external flow field of two different aircraft models is established and meshed.The aerodynamic heating effect on the aircraft skin and how did it effect the distribution of temperature of aircraft skin under subsonic and supersonic speed are discussed.At the same time,established the 3D geometric grid of the axisymmetric vector nozzle and the 2D grid of the Laval-contraction-expansion nozzle.Discussed the temperature and composition distribution of the wake field under the two nozzles and compared the effect of different turbulence models on the calculation results of the tail flame in Fluent.Finally,according to the numerical values obtained by computational fluid dynamics,established the infrared radiation model of the aircraft target and obtained the simulation images of the top view and the horizontal view of the aircraft target in the 3-5?m continuous band.Analyzed the radiation characteristics of these two directions.Starting from the ray tracing method and combining the infrared radiation transmission theory,the numerical values simulated by the computational fluid dynamics method are used to generate the infrared image of the aircraft.The obtained image has the characteristics of high precision and high realism,and can be used for the research on the stealth and detection performance of the aircraft target in the infrared band.