Analysis Of Dynamic Heat Transfer And Research On Thermal Control Technology In Micro-satellite

Micro-satellite technology is a focus of research in astronautics domain because of its short leadtime、low cost and low risk. Traditional thermal control technologies received challenge from thedevelopment of miniaturized satellite. Micro-satellite with low thermal inertia must have an instabilitytemperature. Micro-satellite thermal control technology will be benefit from the research about therules of dynamic heat transfer, analysis method of dynamic temperature and the technology ofdynamic experiment. The research content based on that of this article is summarized:Two-layer model with lumped parameters was built. After the analytic solutions of temperaturemean value was gained, the the analytic solutions of temperature fluaction value was aquired bymeans of Fourier transform (FFT). The uniformity between analytic solution and numerical solutionwas researched. Making an analogy with damping oscillatory system, the rules of amplitudecharacterictics and phase characterictics were researched by means of transfer function in frequencydomain, which standed for transfer relation of amplitude and phase between the heat fluaction andtemperature fluaction. Based on that, The theramal control designing method of “optimum dynamictemperature range” was brought forward.Under the high and low temperature conditions for designing obit parameters, the passivethermal control system of some micro-satellite was designed. The designing scheme of thermalcontrol system was gained through the computing of designing parameters and designing of thethermal control method, according to thermal control designing method of “optimum dynamictemperature range”, which gived an example for this method. Corresponding and not corresponding to“optimum dynamic temperature range” thermal control design were compared by means of numericalsimulation, the result gave evidence to the validity of designing method. Based on that, The designingidea of new thermal control layout “appropriate heat insulation-heat radiation through circumference”was raised. Maching the traditional thermal control layout “whole heat insulation-heat radiationthrough radiating surface”, new layout was superior on mass and reliability.The accuracy of infrared heating cage imitating dyramic heat flux was low due to heat flowmeter of steady calibration. Heat flow meter was calibrated by dynamic method, and thediscriminating and controlling of dyramic parameters was used, in order to improve the the accuracyof imitating gently changing dyramic heat flux. The way of outputing power adjusting with open-loopcontrol was used, in order to sovle the accuracy problem when dyramic heat flux changed with a largescope in a moment. The effect of improving method was proved by the result of thermal equilibriumexperiment. Some micro-satellite’s thermal equilibrium experiment was launched. The rules of dyramictemperatures is compared between corresponding and not corresponding to “optimum dynamictemperature range” thermal control design, it proves that thermal control designing method of“optimum dynamic temperature range” is effective. The telemetering temperature in orbit showed nodifference with the result of numerical simulation and experiment, it gave beneficial evidence to thenew thermal control designing method and new layout designing idea.Based on buliting the parameter assembling, dynamic thermal analysis model was revisedthrough Montecarlo mixing method layer by layer, in which the high temperature condition data ofdynamic experiment was standard. Dynamic temperature error was seted up and used to evaluate therevising effect. The influence of specific heat capacity to revising effect of dynamic thermal analysismodel was discussed. The revising method’accuracy was proved by comparing the numericalsimulation and experiment data under low temperature and special conditions. The applying effect inthermal vacuum experiment and dynamic temperature evalution in orbit also gave evidence to that.The research of this article supported a new thought of thermal control designing method formicro-satellite, a new imitating method to dynamic thermal equilibrium experiment, a new referenceto raise the accuracy of analysis.