Transactions of the Korean Society of Mechanical Engineers B (대한기계학회논문집B)

The Korean Society of Mechanical Engineers (대한기계학회)
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Experimental Investigation of Variable Emittance Material Based on (La, Sr)MnO3

(La, Sr)MnO3을 이용한 가변 방사율 소재에 관한 연구

  • Han, Sunwoo (Dept. of Mechanical Engineering, Korea Advanced Institute of Science and Technology) ;
  • Choi, Bongsu (Dept. of Mechanical Engineering, Korea Advanced Institute of Science and Technology) ;
  • Song, Tae-Ho (Dept. of Mechanical Engineering, Korea Advanced Institute of Science and Technology) ;
  • Kim, Sun Jin (Dept. of Mechanical Engineering, Korea Advanced Institute of Science and Technology) ;
  • Lee, Bong Jae (Dept. of Mechanical Engineering, Korea Advanced Institute of Science and Technology)
  • 한선우 (한국과학기술원 기계공학과) ;
  • 최봉수 (한국과학기술원 기계공학과) ;
  • 송태호 (한국과학기술원 기계공학과) ;
  • 김성진 (한국과학기술원 기계공학과) ;
  • 이봉재 (한국과학기술원 기계공학과)
  • Received : 2012.11.29
  • Accepted : 2013.03.19
  • Published : 2013.06.01
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Abstract

Variable emittance radiators can be used in a thermal management system in space because their total emittance changes depending on the temperature of the system. When the temperature of the system decreased, the emittance also decreased so as to minimize the heat loss to the environment. In contrast, when the temperature of the system increased, the emittance also increased such that radiation cooling could occur. Thermochromic materials, whose emittance is a function of the temperature, are often used in variable emittance radiators because no additional parts are needed. In this study, we fabricated a variable-emittance coating by using a sol-gel method based on LSMO ($La_{1-x}Sr_xMnO_3$) and experimentally characterized the emittance change with respect to temperature. Furthermore, we also examined the stability of LSMO film in space environments by exposing it to extremely low pressure and temperature.

가변 방사율 라디에이터는 우주환경에서 작동하는 장비의 온도가 낮을 때는 방사율이 낮아져 시스템의 외부로의 열 손실을 줄이고, 반대로 온도가 높은 때는 방사율이 높아져 장비의 열을 외부로 방출할 수 있어 효율적인 열제어가 가능하게 한다. 가변 방사율 소재로 보편적으로 이용하고 있는 것 중 하나인 감온변색 장치(thermochromics device)는 추가적인 장비 필요 없이 열제어가 가능하기 때문에 효율적이고 고장이 발생하지 않는 장점을 가지고 있다. 본 연구는 이와 같은 이유로 감온변색 장치의 소재 중 하나인 LSMO($La_{1-x}Sr_xMnO_3$)채택하여 졸-겔(sol-gel)방법을 이용하여 제작하고, 제작된 샘플의 가변방사 성능을 실험적으로 규명하였다. 또한, 진공환경과 극저온 환경에 반복 노출시켜 시편이 극심한 환경 변화 이후에도 방사율 값이 일정함을 확인하여 우주적합성을 판단하였다.

Keywords

References

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