Study On The Key Technique Of Thermal Control For Solar X-Ray And Extreme Ultraviolet Imager

The Solar X-Ray and Extreme Ultrav iolet Imager(XEUVI)is an important remote sensing instrument on the Fengyun-3 satellite.The XEUVI is adopted integrated design of X-ray grazing incidence and extreme u ltravio let(EUV)positive incidence,which is first proposed internationally and is successfully designed in China.XEUVI is the latest space solar observation instrument in China.Its structure is complex,and its pose is changeable.At the same time,its low-temperature detector moves in three dimensions and works for a long time.A ll of the factors will put fo rward new challenges to the thermal design.Based on the thermal design difficult ies of the XEUVI,this paper will focus on three key technologies,such as calculation of external heat flu xes on spac e camera with two-d imensional changing attitudes,thermal control technology of low-temperature detector,and the correction of thermal analysis model.Firstly,the present research status of thermal control technology for typical space probe observing the sun all through the world is introduced.The main methods of observing the sun fro m space,the working characteristics of the detector and the thermal design schemes are summarized.The structural characteristics and working modes of the XEUVI are introdu ced,and the difficult ies of the thermal control system are analyzed.According to the on-orbit working characteristics of the XEUVI,a method to calculate the external heat flu xes of space camera with two-dimensional changing attitudes in J2000 coordinate system is proposed.This method can calculate the real-time attitude angle of the XEUVI,which provides a reference for the attitude setting of the thermal model in thermal analysis calculations.At the same time,the external heat flu xes calculated by the method provides an important basis for the thermal design of the XEUVI.Secondly,a detailed thermal design of low-temperature detector assembly fo r the XEUVI is performed.During the thermal design process,the factors affecting the CCD temperature are qualitatively analyzed.The main factors affect ing the CCD temperature are identified.The corresponding thermal control measures are formu lated to ensure that the CCD meets its operating temperature.In particular,the heat dissipation device of low-temperature detector has been optimized.This device not only meets the requirements of large temperature d ifferences between the low-temperature detector and surrounding components,but also meets the requirements of the detector to move in three directions.Based on the thermal design,a thermal balance test is performed on the low-temperature detector assembly.The test results show that the temperature range of the CCD is fro m-69.2 °C to-50.8 °C,which meets the requirements of thermal control indicators.The thermal design is reasonable and feasible.Thirdly,the optical-mechanical structure and on-orbit observation characteristics of the XEUVI are introduced.The thermal design of each assembly of the imager is detailed.The detailed thermal design of each assembly for the XEUVI is co mpleted.Thermal analysis model is established with I-deas / TMG software,and thermal analysis calculation is performed.The results of thermal simu lation analysis show that the temperature of each assembly meets the requirements of thermal control index.The thermal control system can guarantee the XEUVI to work normally.Finally,depend on the thermal design of the XEUVI,the thermal balance tests of the whole mach ine and the whole star are carried out,respectively.The results of the thermal balance test show that the temperature of each assembly satisfies the thermal design requirements,verify ing the correctness of the thermal design.At the same time,on the basis of the results of the whole machine thermal balance test,a thermal analysis model correction method based on latin hypercube sampling and coordinate rotation method is proposed.When the model is corrected,the thermal model correction is based on the test results at high-temperature condition.The low-temperature condition is used to verify the result.The deviation between the thermal analysis calculat ion and the thermal balance test before and after the correction is compared.The corrected results show that the maximu m deviation is reduced from 11.5 ° C to 1 ° C under high-temperature conditions,and 70% of the deviations are less than 0.5 ° C.The maximu m deviation is under low-temperature conditions is reduced from 11.5 °C to 2 °C,and the deviation of 75% is not more than 1.5 °C.The results turn out that this method can effectively correct the thermal analysis model.