Image Simulation Method Of Aircraft Tail Flame Based On Ray Tracing

As an important basis for the detection,tracking and recognition of aircraft target,the radiation signal of tail flame has always been an important research content in the field of national defense aerospace.At present,due to the lack of measured sample data and the harsh experimental conditions,the research of tail flame image simulation method is very important.Combined with the above application background,based on the actual needs of more realistic and physical laws of the plume image,this paper proposes a method of aircraft plume image simulation combined with the idea of ray tracing by analyzing the current research situation of flow field simulation technology and radiation transmission solution model.The research work of this paper is carried out from the following three aspects:Firstly,according to the basic theory of fluid mechanics and the basic model of computational fluid mechanics,the CFD software FLUENT is selected to complete the flow field modeling,and the specific modeling process of the wake flow field is introduced.In order to complete the modeling work of the plume flow field,the simulation calculation of the plume flow field under the condition of adding inert particle flow is emphasized,and the influence of this condition on the modeling results is analyzed briefly.Then,in terms of the calculation method of the component radiation characteristic parameters of the tail flame,through the analysis of the physical process of the radiation transmission of the tail flame,the infrared radiation transmission model of the tail flame is established,and the radiation characteristic parameters in the model are calculated based on the flow field data of the tail flame obtained from the simulation modeling.This part of research work mainly includes: considering the broadening effect of gas spectral line,using the line by line integration method to calculate the radiation characteristic parameters of high temperature gas;considering the self emission,absorption and scattering effect of solid spherical particles,using Mie scattering theory to calculate the radiation characteristic parameters of spherical particles.Finally,in the aspect of solving method of radiation transfer of tail flame,based on the idea of finite element,the simulation data of tail flame flow field is discretized and gridded,and the corresponding ray tracing algorithm of tail flame area is designed.According to the ray tracing algorithm,the integrated problem of tail flame radiation transfer is solved by using the reverse Monte Carlo method,and the work of tail flame radiance image simulation is completed.In addition,in the near infrared,mid infrared and long infrared bands,the method proposed in this paper is used to simulate and calculate the tail flame radiation intensity under different detection angles and different wavelengths with or without inert particle flow.Through the comparative analysis of the calculation results,the correctness and feasibility of the tail flame image simulation method based on ray tracing in this paper are verified.