Simulation And Research On Thermal Radiation Effects Of Supersonic Opitcal Window

Supersonic aircraft equipped with infrared imaging system in the course of flight,the air temperature of the aircraft is rising rapidly due to the aerodynamic thermal radiation effect,and the temperature of the aircraft optical window is elevated by the high temperature.Infrared window produces a strong infrared radiation,on the receiver surface of the detector to form a radiation background,resulting in a decrease in imaging quality of infrared detection system,even will make the detection system ineffective.Therefore,the research on the aerodynamic thermal radiation effect of highspeed aircraft is of great significance in guidance.In this paper,the research status of aerodynamic optical effects at home and abroad is investigated,the main research done by scholars at home and abroad and the future development direction are analyzed.The simulation and analysis of the generation and propagation of the aerodynamic heat radiation and the effect of the final detection surface imaging are carried out.Firstly,the aircraft is modeled,divided into grids,according to the aerodynamics principle and the finite element software,the model grid is divided,the boundary condition and the flight state are set up,and the temperature distribution of the external gas in the flying process of the aircraft is simulated.As the temperature of the gas flow field rises,the outer surface of the window is heated,and heat transfer is carried out to the inner surface of the window.According to the energy equation in the heat conduction process and the infrared window material and size,the finite element method is used to model the plate type and hemispherical infrared window respectively,and the temperature distribution of the window is obtained.At the same time,the transmittance of IR window is analyzed theoretically,and based on an approximate theory,the simulation experiment is designed to get the corresponding data,and the window transmittance is obtained by fitting calculation.Then by using Monte Carlo method,the heat radiation propagation is studied theoretically,the Cassegrain infrared detection optical system is selected,the parameters are calculated and set up,and the infrared radiation image is obtained by using ray tracing method in the detection surface.At the same time,a series of influence parameters such as thermal radiation detection distance and detection angle and lens in infrared optical system are analyzed.The effect of aerodynamic thermal radiation is evaluated by the experimental results.This paper simulates the whole process of the formation and propagation of aerodynamic heat radiation to the detection by means of computer simulation,and the feasibility and applicability of the simulation method can be seen from the process and the result,which provides the method reference and data support for the study of aerodynamic thermal radiation effect of hypersonic vehicle.