Journal of the Korean Society of Propulsion Engineers (한국추진공학회지)

The Korean Society of Propulsion Engineers (한국추진공학회)
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Investigation of Drop Test Method for Simulation of Low Gravity Environment

저중력 환경 모사를 위한 낙하 시험 방법 연구

  • Baek, Seungwhan (Launcher Propulsion System Team, Korea Aerospace Research Institute) ;
  • Yu, Isang (Launcher Propulsion System Team, Korea Aerospace Research Institute) ;
  • Shin, Jaehyun (Aerospace Team, EPC Division, Hanyang ENG) ;
  • Park, Kwangkun (Launcher Propulsion System Team, Korea Aerospace Research Institute) ;
  • Jung, Youngsuk (Launcher Propulsion System Team, Korea Aerospace Research Institute) ;
  • Cho, Kiejoo (Launcher Propulsion System Team, Korea Aerospace Research Institute) ;
  • Oh, Seunghyub (Launcher Propulsion Development Division, Korea Aerospace Research Institute)
  • Received : 2021.04.23
  • Accepted : 2021.06.13
  • Published : 2021.08.31
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Abstract

Understanding the liquid propellant transport phenomena in low gravity is essential for developing Korea Space Launch Vehicle (KSLV) upper-stage for the diversity of space missions. A low-gravity environment can be simulated via the free-fall method on the ground; however, the air drag is inevitable. To reduce air resistance during free fall, air-drag shield is usually adopted. In this study, the free-fall method was performed with an air-drag shield from a 7-m height tower. The acceleration of a falling object was measured and analyzed. Low gravity below 0.01 g was achieved during 1.2-s free fall with the air-drag shield. The minimum gravitational acceleration value at 1.2-s after free fall was ±0.005 g, which is comparable to the value obtained from Bremen drop tower experiments, ±0.002 g. A prolonged free-fall duration may enhance the low-gravity quality during the drop tower experiments.

KSLV 상단의 임무 다각화를 위해서는 저중력 환경에서 액체 추진제의 거동을 정확히 파악하고 있어야 한다. 지상에서 저중력 환경을 모사하는 방법은 자유낙하 방법이 있지만, 공기저항이 항상 동반된다. 공기 저항을 제거하기 위하여 공기 저항 차단캡슐을 이용한 낙하 시험을 진행하였다. 공기 저항 차단캡슐 내부에 시험체를 위치하고 7 m 높이에서 1.2초 동안 낙하하여 시험체의 저중력 환경을 조성하였다. 낙하하는 동안 0.01 g 이하의 중력가속도를 측정하였으며 지표면에 도달하기 전 최소 가속도는 약 0.005 g였다. 추후 낙하 높이 및 낙하 시간이 증가한다면 개선될 수 여지가 있다.

Keywords

Acknowledgement

본 연구는 한국형발사체개발사업의 지원을 받아 진행되었습니다.

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