Simulation Research On Infrared Radiation Characteristics Of Aircraft Based On OpenMP Parallel Computing

Infrared radiation characteristics are important parameters for detecting,identifying and striking aircraft in the context of systematic countermeasures.On the one hand,the infrared radiation characteristics of the aircraft can be received by infrared detectors as a radiation source,so that the countermeasure system can identify,track,lock,strike and interfere with the target according to the received infrared radiation characteristics;The simulation platform can simulate wartime infrared confrontation in advance,improve the infrared stealth performance of the aircraft,and develop effective infrared interference methods.Different forms of detectors,such as space-based detectors and land-based detectors,have different sensitivity to different parts of the aircraft,and the infrared radiation characteristics of the aircraft under different flight states,wavelengths and detection angles are also different.To obtain infrared measured data under arbitrary conditions,it is of great engineering significance to build a simulation platform for aircraft infrared radiation characteristics under complex environmental conditions for combat simulation training,combat strategy designation,target identification and tracking,and infrared countermeasures.In this paper,the infrared radiation characteristics of the aircraft are decomposed into skin and tail flame in the numerical simulation,and according to the characteristics of numerical calculation,the parallel acceleration is completed by using Open MP.For skin radiation,use Catia to complete geometric modeling,and use Gid to complete model meshing.According to the above discrete meshes,the finite element method solution model of the skin temperature field is established,and the typical boundary conditions such as solar irradiation,ground reflection,aerodynamic heating,and convective cooling under different time and space are considered and converted into the load matrix of the finite element method.Finite element stiffness matrix and load matrix Write C++ serial code to solve the skin temperature field distribution.According to the above temperature field distribution,the infrared emission of the skin in two typical bands of mid-wave infrared and long-wave infrared is obtained,and the reflected infrared characteristics of the skin are obtained by combining the bidirectional reflection distribution function model and the traditional diffuse reflection model.The reflection solver detects in-plane skin omnidirectional infrared radiation features.According to the characteristics of the serial code of skin infrared radiation features,the data structure of the parallel region is organized,and the multi-thread acceleration solution of the parallel region for the skin infrared radiation feature is completed by using Open MP.For the tail flame,the initial flow field data of the converging-expanding nozzle is generated with the help of Fluent,and the calculation flow field grid is obtained by organizing five times inverse distance interpolation.The basic physical property databases of different versions of HITRAN and HITEMP were compared,and their influence on the solution of gas absorption coefficient and radiation intensity was analyzed.Combining the line-by-line calculation method and the Malkmus statistical narrow-band model to solve the spectral absorption coefficient of the pure absorbing plume gas,using C++ to write a serial calculation program to solve the apparent ray method in the single wavelength and the mid-wave infrared and long-wave infrared two bands Radiation intensity distribution to obtain the integral radiation intensity distribution of the detection plane under different detection viewing angles.According to the characteristics of the tail flame radiation solution code,three Open MP parallel computing blocks are organized to solve three Open MP multi-threaded parallel computing blocks,including inverse distance interpolation,line-by-line calculation method and apparent ray method,and analyze the influence of the number of threads on the acceleration efficiency and acceleration ratio.Based on the independent solution of flame radiation,the integrated calculation code of skin-puff infrared radiation is developed.