Journal of the Korean Society of Marine Environment & Safety (해양환경안전학회지)

The Korean Society of Marine Environment and safety (해양환경안전학회)
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Design and Analysis of a Mooring System for an Offshore Platform in the Concept Design Phase

해양플랜트 개념설계 단계에서의 계류계 초기 설계 및 해석

  • Sungjun Jung (Deep Ocean Engineering Research Center, Korea Research Institute of Ships & Ocean Engineering) ;
  • Byeongwon Park (Deep Ocean Engineering Research Center, Korea Research Institute of Ships & Ocean Engineering) ;
  • Jaehwan Jung (Deep Ocean Engineering Research Center, Korea Research Institute of Ships & Ocean Engineering) ;
  • Seunghoon Oh (Deep Ocean Engineering Research Center, Korea Research Institute of Ships & Ocean Engineering) ;
  • Jongchun Park (Department of Naval Architecture and Ocean Engineering, Pusan National University)
  • 정성준 (선박해양플랜트연구소 심해공학연구센터 ) ;
  • 박병원 (선박해양플랜트연구소 심해공학연구센터 ) ;
  • 정재환 (선박해양플랜트연구소 심해공학연구센터 ) ;
  • 오승훈 (선박해양플랜트연구소 심해공학연구센터 ) ;
  • 박종천 (부산대학교 조선해양공학과 )
  • Received : 2023.03.23
  • Accepted : 2023.04.27
  • Published : 2023.04.30
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Abstract

Most offshore platforms utilize chain mooring systems for position keeping. However, information regarding related design modification processes is scarce in literature. This study focuses on the floating liquefied natural gas (LNG) bunkering terminal (FLBT) as the target of shore platform and analyzes the corresponding initial mooring design and model tests via numerical simulations. Subsequently, based on the modified design conditions, a new mooring system design is proposed. Adjusting the main direction of the mooring line bundle according to the dominant environmental direction is found to significantly reduce the mooring design load. Even turret-moored offshore platforms are exposed to beam sea conditions, leading to high mooring tension due to motions in beam sea conditions. Collinear environmental conditions cannot be considered as design conditions. Mooring design loads occur under complex conditions of wind, waves, and currents in different environmental directions. Therefore, it is essential appropriately assign the roll damping coefficients during mooring analysis because the roll has a significant effect on mooring tension.

대다수의 부유식 해양플랜트는 위치 유지의 방법으로서 체인 계류 시스템을 사용하나, 그 설계 변경 과정은 논문으로 찾아보기 힘들다. 본 연구는 FLBT를 대상 해양플랜트로 선정하여 계류 초기설계안과 모형시험을 수치해석으로 분석하고, 변경된 설계조건에 따라 새로운 계류 설계안을 제시하였다. 주된 환경 방향에 따라 계류선 묶음(bundle)의 주 방향을 조절하는 것이 계류 설계하중 감소에 크게 유효했다. 터렛 계류된 해양플랜트라도 횡파에 노출되며, 횡파 중 운동 때문에 높은 계류 인장력이 발생했다. 일치된 환경 방향 조건은 설계조건이 될 수 없으며, 바람, 파도, 조류의 각 환경 방향이 복잡한 조건에서 설계 계류 하중이 발생했다. 횡요 운동이 계류 인장력에 미치는 영향이 큼으로 적절한 횡요 감쇠 계수를 계류해석에 적용하는 것이 중요하다.

Keywords

Acknowledgement

본 논문은 해양수산부 재원으로 선박해양플랜트연구소의 주요사업인 "심해용 복합해양 플랫폼 통합 성능평가 기술개발"에 의해 수행되었습니다(PES4760).

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