Study on Flow Characteristics and Discharge Coefficient of Safety Valve for LNG/LNG-FPSO Ships

LNG / LNG-FPSO 선박용 안전밸브의 유동특성 및 유출계수에 관한 연구

  • Kim, Sung-Jin (Dept. of Creative Engineering System, Pusan Nat'l Univ.) ;
  • Jung, Sung-Yuen (Research Institute of Mechanical Technology, Pusan Nat'l Univ.) ;
  • Kim, Dang-Ju (Research Institute, Korval Co., Ltd.) ;
  • Kim, Chul (Research Institute of Mechanical Technology, Pusan Nat'l Univ.)
  • 김성진 (부산대학교 창의공학시스템학과) ;
  • 정성윤 (부산대학교 기계기술연구원) ;
  • 김당주 ((주)코밸 연구소) ;
  • 김철 (부산대학교 기계기술연구원)
  • Received : 2010.09.06
  • Accepted : 2011.02.25
  • Published : 2011.05.01


The safety valve used in LNG/LNG-FPSO ships plays an important role in maintaining a fixed level of pressure by emitting LNG gas out of the pipes in the LNG piping system. The discharge coefficient is regarded as the most important factor in the valve performance. To satisfy the ship's classification, the discharge coefficient of the safety valve must usually be over 0.8. Despite the importance of understanding the flow phenomena inside the safety valve, the valve design is usually based on experience and experiments. We carried out a computational fluid dynamics (CFD) investigation using the ANSYS-CFX software. We observed the flow phenomena inside the valve and measured the discharge coefficients according to changes in the valve lift, which is the distance between the exit of the nozzle and the lower part of the disc plate. We verified our CFD results for the discharge coefficients using available experimental data.


Safety Valve;Discharge Coefficient;Compressible Flow;Computation Fluid Dynamics;Shock Wave


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