Development Of Thermal Analysis And Infrared Simulation Software For Satellite Orbiting The Earth

Satellite is the main tool for human to explore the space.Accurate and efficient calculation of the transient temperature field distribution of the satellite in the orbital thermal environment is a necessary part of satellite thermal control analysis and design,and also a key step in satellite infrared simulation.Nowadays,commercial aerospace is booming,and micro-nano satellites are gradually becoming the new mainstream satellite products.For these new satellites,accurate thermal analysis is more urgently.However,most of the mature thermal analysis softwares at the current stage are developed by foreign teams with low accuracy,and domestic software for satellite thermal analysis is more deficient.In this paper,the development of the geothermal analysis and infrared simulation software for ground-based flight satellites is carried out based on the Fortran self-programming method.The self-programming satellite thermal analysis software is used to simulate the orbital thermal environment of the orbiting satellites in the orbital thermal environment.In this paper,the theory of satellite thermal analysis is briefly introduced.The thermal analysis calculation of satellite mainly includes three aspects: orbit parameter calculation,extraspace heat flow calculation and temperature calculation.In the satellite centroid orbit coordinate system,a simulation model of simple and fast solution of solar vector and earth vector is established.The changes of posture and occlusion judgment methods are introduced.Based on this,the derivation of extra-space heat flow is completed.The finite volume method for solving the temperature field of 3D model is deduced and the boundary conditions are unified.A method for solving the infrared radiation characteristics considering self-emission and background reflection is deduced.The main program programming of the self-programming satellite thermal analysis software was completed by using Fortran language and the self-programming software was packaged through visual programming.The self-programming satellite thermal analysis software can accurately solve the external heat flow,temperature field and infrared radiation characteristics of non-spin satellites flying around any day,in-orbit position,and elliptical orbital parameters.In the process of solving,the effects of extra-space heat flow,environmental radiation,the target's own radiation emission,and radiation occlusion between components are considered.The correctness of the thermal conduction part and the radiation occlusion judgments of the software was verified by Fluent.The calculation results of the selfprogramming software were basically consistent with the Fluent verification results.The radiant heat conduction coupling heat transfer of the multi-body system under vacuum low temperature conditions was carried out.The experimental verification shows that the error between the experimental results and the self-compiled software calculation results is kept within 3K.The orbital thermal environment of an elliptical orbit near-Earth satellite was simulated by self-programming satellite thermal analysis software,and the calculation results were analyzed and discussed in detail.The external heat flow of the satellite's outer surface has a significant periodicity and is greatly affected by the changes of posture.The solar radiation accounts for the largest proportion,the earth's infrared is second,and the earth's albedo has the smallest proportion.The temperature field of the satellite is mainly affected by the heat flow outside the space and the internal heat source of the satellite.The radiation force of the satellite in the nearinfrared band(3-5?m)is one order of magnitude lower than that in the far-infrared band(8-12?m).When performing satellite infrared simulation,the reflected radiation of the satellite to the background cannot be ignored.The thermal analysis and calculation of variable orbit parameters of a satellite are carried out.It can be seen from the analysis results of the orbital parameters that the orbital parameters are one of the important influencing factors of the instantaneous high/low temperature of the satellite in orbit.The sensitivity analysis of the typical thermal properties of the satellite was carried out.From the sensitivity analysis results,it can be seen that the temperature of the whole star is very sensitive to the surface coating of the satellite.