탄소복합재를 이용한 위성 패널의 열해석

전형열(Hyoung Yoll Jun),김정훈(Jung Hoon Kim),박종석(Jong Seok Park),박근주(Keun Joo Park) 한국항공우주연구원 2011 항공우주기술 Vol.10 No.2

인공위성의 효율적인 열제어를 위해 알루미늄으로 만들어진 하니콤 패널과 OSR로 구성된 방열판을 사용한다. 또한 추가적으로 발열량이 많은 부품의 경우, 알루미늄으로 만들어진 더블러와 히트파이프 등을 이용하여 열제어를 수행한다. 최근 위성 전장 부품의 발열량의 증가로 정해진 위성의 크기, 발사 중량 및 비용으로 더 많은 열을 외부로 효율적으로 방출할 수 있는 방열 능력향상에 대한 필요성으로 새로운 열제어 물질에 대한 연구가 진행 중이다. 특히, 탄소 복합재는 일반적으로 열전도가 매우 높고, 가볍고, 기계적 강성에 좋은 특성이 있어 차세대 열제어를 위한 물질로 많은 연구가 진행되고 있다. 본 논문에서는 차세대 탄소 복합재인, APG(Annealed Pyrolytic Graphite)와 탄소-탄소 복합재(carbon-carbon composites)를 이용하여 통신패널의 열제어를 수행하는 경우와 기존의 열제어 방식과의 차이를 수치적으로 비교하였다. Thermal control of satellite is mainly based on passive ways, such as the radiator made of aluminum honeycomb core with aluminum skins and OSR (Optical Solar Reflector). Additionally, for the thermal control of high dissipation unit, the aluminum doubler and heat pipe are utilized. Recently, efforts to find advanced thermal materials have been carried out to enhance heat rejection capability without increasing satellite size, weight and cost. This paper handles the carbon composites have high thermal conductivity with light weigh and have been considered as future thermal control materials to replace aluminum based radiator and doubler. Thermal analysis of satellite panel using APG(Annealed Pyrolytic Graphite) and carbon-carbon composites were performed and temperature contours were compared with the conventional thermal control methods.

정지궤도복합위성(GK2A)의 열진공 시험 및 시험 예측에 관한 연구

전형열(Jun, Hyoung Yoll),김정훈(Kim, Jung-Hoon),현범석(Hyun, Bum-Seok),박근주(Park, Keun Joo) 한국항공우주연구원 2018 항공우주산업기술동향 Vol.16 No.1

정지궤도복합위성(GK2A)는 한국항공우주항우연이 독자적으로 개발하는 3.5톤급의 국내 최초의 정지궤도 위성이다. GK2A는 기상관측을 주 임무로 수행하며, 2010년 발사되어 현재 운용중인 천리안 위성을 대체하기 위해 개발 중이다. 2018년 하반기에 Ariane 5호 발사체를 이용하여 발사될 목표로 현재 조립 및 환경시험을 수행 중에 있다. 2018년 5월 8일, 열진공 시험을 완료하였으며, 이 열진공 시험은 열제어 설계 검증, 열제어 하드웨어 작동 검증, 열해석 모델 보정 및 우주궤도환경하에서 위성전반에 대한 기능 시험을 주목적으로 한다. GK2A 위성의 열진공 시험은 한국항공우주연구원에서 자체 개발한 대형 열진공 챔버를 이용하여 수행되었다. 또한 정지궤도에서의 외부 열유입량을 모사하기 위해, 위성의 남쪽과 북쪽 방열판위에 각각 독립된 액화질소 및 질소가스를 이용하는 히팅플레이트를 장착하였다. 본 논문에서는 정지궤도복합위성의 열진공 시험 방법, 열진공 시험 예측을 위한 모델링, 열진공 시험 예측 및 실제 열진공 시험에 관해 다루고자 한다. KARI is developing independently GEO-KOMPSAT-2A(GK2A), which is the first 3.5 ton class geostationary satellite in Korea. The mission of GK2A is the meteorological observation and it will take over the meteorological mission of COMS launched at 2010. GK2A has been performing the environmental tests and will be launched the end of this year by Ariane 5 launcher. The thermal vacuum test was conducted until 8th May 2018 to validate thermal control design, to validate satellite functions under the simulated space environments and to obtain data for thermal model correlation. The thermal vacuum test was carried out by using the large thermal vacuum chamber developed by KARI. Additionally, the radiating(or heating) plates were installed on the front of the north and south panel of GK2A in order to simulate the external solar flux at the geostationary orbit. The temperatures of the plates were controlled by circulating GN2 and LN2. This paper describes the thermal vacuum test method, the thermal modelling, the test prediction and the test results of GK2A.

PAT 기반 온도장 보간을 이용한 관측위성의 열지향오차해석

임재혁(Jae Hyuk Lim),김선원(Sun-Won Kim),김정훈(Jeong-Hoon Kim),김창호(Chang-Ho Kim),전형열(Hyoung-Yoll Jun),오현철(Hyeon Cheol Oh),신창민(Chang Min Shin),이병채(Byung Chai Lee) 한국항공우주학회 2016 韓國航空宇宙學會誌 Vol.44 No.1

본 논문에서는 계절 및 주야의 온도변화를 고려한 관측위성의 열지향오차해석을 실시한다. 관측위성은 임무수행기간 동안 다채널의 관측센서를 이용해서 지구표면의 영상을 촬영한다. 그러나 주야 및 계절별로 최대 200도의 온도환경 차이가 발생하며 이로 인해 관측센서 및 별추적기의 시선벡터가 변화되고 정해진 목표지점의 영상촬영이 어렵다. 이런 문제를 사전예측하고 대응하기 위해서 열지향오차해석을 실시한다. 우선 궤도열환경해석으로부터 도출된 성긴 온도장 정보를 상세한 구조유한요소모델에 PAT기법을 이용해 보간하여 온도변화에 따른 열변형해석을 수행하였다. PAT로 보간된 온도분포의 정확도를 검증하였으며, 열변형해석결과로부터 열지향오차를 도출하였다. In this work, we conduct a thermal pointing error analysis of the observation satellites considering seasonal and daily temperature variation with interpolated temperature based on prescribed average temperature (PAT) method. Maximum 200 degree temperature excursion is applied to the observation satellites during on-orbit operation, which cause the line of sight (LOS) to deviate from the designated pointing direction due to thermo-elastic deformation. To predict and adjust such deviation, the thermo-elastic deformation analysis with a fine structural finite element model is accomplished with interpolated thermal maps calculated from the results of on-station thermal analysis with a coarse thermal model. After verifying the interpolated temperatures by PAT with two benchmark problems, we evaluate the thermal pointing error.

3.5 톤급 정지궤도 위성의 열평형 시험 결과를 이용한 열해석 모델 보정

전형열(Hyoung Yoll Jun),한경아(Kyung-Ah Han),김정훈(Jung Hoon Kim),김상호(Sang-Ho Kim),박근주(Keun Joo Park),장병관(Byung-Kwan Jang) 한국항공우주학회 2018 한국항공우주학회 학술발표회 논문집 Vol.2018 No.11

SMA(SHAPE MEMORY ALLOY) ACTUATOR USING FORCED CONVECTION

전형열(Hyoung Yoll Jun),김정훈(Jung-Hoon Kim),박응식(Eung Sik Park) 한국전산유체공학회 2005 한국전산유체공학회지 Vol.10 No.2

This work discusses the numerical analysis, the design and experimental test of the SMA actuator along with its capabilities and limitations. Convective heating and cooling using water actuate the SMA(Shape memory alloy) element of the actuator. The fuel such as propane, having a high energy density, is used as the energy source for the SMA actuator in order to increase power and energy density of the system, and thus in order to obviate the need for electrical power supplies such as batteries. The system is composed of a pump, valves, bellows, a heater(burner), control unit and a displacement amplification device. The experimental test of the SMA actuator system results in 150 MPa stress(force : 1560 N) with 3 % strain and 0.5 Hz actuation frequency. The actuation frequency is compared with the prediction obtained from numerical analysis. For the designed SMA actuator system, the results of numerical analysis were utilized in determining design parameters and operating conditions.

천리안2A호 열제어 설계 및 열제어계 전이궤도 운영 결과

전형열(Hyoung Yoll Jun),김정훈(Jung-Hoon Kim) 한국항공우주학회 2019 한국항공우주학회 학술발표회 논문집 Vol.2019 No.4

정지궤도 위성의 영평형 시험 모델링 및 예비 예측

전형열(Hyoung Yoll Jun),김정훈(Jung-Hoon Kim) 한국전산유체공학회 2009 한국전산유체공학회 학술대회논문집 Vol.2009 No.4

COMS (Communication, Ocean and Meteorological Satellite) is a geostationary satellite and has been developing by KARI for communication, ocean and meteorological observations. It will be tested under vacuum condition and very low temperature in order to verify thermal design of COMS. The test will be performed by using KARI large thermal vacuum chamber, which was developed by KARI, and the COMS will be the first flight satellite tested in this chamber. The purposes of thermal balance test are to correlate analytical model used for design evaluation and predicting temperatures, and to verify and adjust thermal control concept. KARI has plan to use heating plates to simulate space hal condition especially for radiator panels such as north and south panels. They will be controlled from 90K to 273K by circulating GN2 and LN2 alternatively according to the test phases, while the shroud of the vacuum chamber will be under constant temperature, 90K, during all thermal balance test. This paper presents thermal modelling including test chamber, heating plates and the satellite without solar array wing and Ka-band reflectors and discusses temperature prediction during thermal balance test.

통신해양기상위성의 전이궤도 열해석

전형열(Hyoung Yoll Jun),김정훈(Jung-Hoon Kim),김성훈(Sung-Hoon Kim),양군호(Koon Ho Yang) 한국전산유체공학회 2008 한국전산유체공학회지 Vol.13 No.2

COMS (Communication, Ocean and Meteorological Satellite) is a geostationary satellite and has been developing by KARl for communication, ocean and meteorological observations. It will be launched by ARIANE 5. Ka-band components are installed on South panel, where single solar array wing is mounted. Radiators, embedded heat pipes, external heat pipe, insulation blankets and heaters are utilized for the thermal control of the satellite. The Ka-band payload section is divided several areas based on unit operating temperature in order to optimize radiator area and maximize heat rejection capability. Other equipment for sensors and bus are installed on North panel. The ocean and meteorological sensors are installed on optical benches on the top floor to decouple thermally from the satellite. During the transfer orbit operation, satellite will be under severe thermal environments due to low dissipation of components, satellite attitudes and LAE(Liquid Apogee Engine) firing. This paper presents temperature and heater power prediction and validation of thermal control design during transfer orbit operation.

히트 파이프가 장착된 정지궤도 위성 패널 열해석 프로그램 개발

전형열(Hyoung Yoll Jun),김정훈(Jung-Hoon Kim),한조영(Cho Young Han),채종원(Jong Won Chae) 한국전산유체공학회 2010 한국전산유체공학회 학술대회논문집 Vol.2010 No.5

The north and south panel of a geostationary satellite are used for radiator panels to reject internal heat dissipation of electronics units and utilize several heat pipe networks to control the temperatures of units and the satellite within proper ranges. The design of these panels is very important and essential at the conceptual design and preliminary design stage, so several thousands of nodes or more are utilized in order to perform thermal analysis of panel. Generating a large number of nodes(meshes) of the panel takes time and is tedious work because the mesh can be easily changed and updated by locations of units and heat pipes. Also the detailed panel model can not be integrated into spacecraft thermal model due to its node size and limitation of commercial satellite thermal analysis program. Thus development of a program was required in order to generate detailed panel model, to perform thermal analysis and to make a reduced panel model for the integration to the satellite thermal model. This paper describes the development and the verification of panel thermal analysis program with ist main modules and its main functions.

외장형 HEAT PIPE가 장착된 정지궤도 위성 패널의 열해석

전형열(H.Y. Jun),김정훈(J.H. Kim) 한국전산유체공학회 2006 한국전산유체공학회지 Vol.11 No.3

The north panel of a geostationary satellite is used as one of the main radiators, on which communication equipment or bus equipment are installed. The thermal control of panel is designed by using embedded heat pipes and surface heat pipes (or external heat pipes) to spread out heat dissipated from equipment all over the radiator evenly and finally to reject the heat to the space through the radiator efficiently. This panel is also divided by several areas based on the operating temperature and dissipation of equipment in order to increase heat rejection capability of radiator. The thermal analysis is carried out for the hot case, Winter Solsitce EOL (End Of Life), in order to validate thermal design of the panel utilized 6 surface heat pipes and 8 embedded heat pipes. The sensitivity studies for the heat pipe failure case and no heat pipe case are performed and compared to its normal state. The heat transport capability of heat pipe is also obtained from these calculations.