On-Orbit External Heat Flow Calculation And Internal Thermal Analysis Of Satellites

With the change of society,the progress of science and technology,and the development of military industry,satellite is increasingly widely used in military production.However,with the improvement of the integration of satellite,the phenomena of high heat flux and low thermal inertia of satellite makes a lot of heat generated in the narrow space of satellite.The accumulated heat seriously affects the normal operation of satellites,and at the same time puts forward more stringent requirements for satellite thermal control system.In order to solve these problems and optimize the satellite thermal control system,it is necessary to analyze the temperature field,thermal stress and thermal deformation of the satellite in orbit more accurately.In order to simplify the appellation,this paper uses "satellite" to refer to "artificial earth satellite".In order to ensure the high efficiency and stability of the satellite,this paper calculates the space external heat flow which causes the non-uniform time-varying temperature field of the satellite,and analyses the temperature field,thermal stress and thermal deformation of the satellite.In order to reduce these impacts,a heat pipe device with high heat transfer efficiency is introduced into the satellite in this paper.It is concluded that the heat pipe system can effectively reduce the non-uniform temperature distribution in the satellite,thus ensuring that the onboard single machine works at the allowable temperature and reduce the thermal deformation of the satellite.This paper provides some references for the calculation of space external heat flow of satellite flying around the earth,the design of satellite with heat pipe and the analysis of temperature field.The main contents of this paper are as follows:1.The variation of extraspace thermal flow in satellite orbit period is analyzed in detail.The space geometric relationship of satellite,sun and earth in the celestial coordinate system is determined by the orbit parameters of satellite.Based on this geometric relationship,the relationship between the angle of solar projection and the ascending intersection point of satellite is discussed.Considering the influence of satellite's self-occlusion and flight attitude,a formula for calculating the external heat flow at any position of the satellite is established.The formula is used to analyze the transient external heat flow on the surface of a satellite in a solar synchronous circular orbit at a specific orbit altitude during an orbit period,which provides an external thermal boundary condition for the analysis of the satellite's temperature field.2.The non-uniform time-varying temperature field of the satellite under the action of external heat flow and the thermal stress and deformation caused by the temperature field are analyzed.According to the thermal transmission mode and boundary condition of satellite in vacuum,the equilibrium equation of satellite node thermal network is established by using the law of conservation of energy.The temperature field,thermal stress and thermal deformation of the satellite are analyzed by linearization method and indirect coupling method.The results show that the non-uniform time-varying temperature field of satellite results in large thermal stress and deformation,and the temperature of partial single machine exceeds the upper limit of permissible operating temperature.3.In this paper,a heat pipe is proposed to solve the problem of satellite heat concentration and high temperature of partial single machine.The effects of heat pipe number and heat transfer coefficient on satellite temperature field and partial single machine are analyzed.The results show that increasing the number of heat pipes and the heat transfer coefficient of the medium in the heat pipe can better realize the homogenization of the temperature of the satellite and partial single machine,and reduce the thermal stress and displacement deformation of the satellite.In this paper,the factors of heat pipe are studied,which can provide some reference for the application of heat pipe in satellite and other fields.