Coupling Effects of Liquid Loading Vessels in the Floating Liquefied Natural Gas System

This study develops a program to investigate the coupling effects between liquid sloshing and vessel's motion in the floating liquefied natural gas (FLNG) system. In the program, hydrodynamic coefficients of vessel in frequency-domain are solved and solution of vessel's motion in time-domain is calculated based on impulsive response function (IRF), liquid sloshing model is built based on potential flow theory and is solved by boundary element method. The solution of vessel's motion and liquid sloshing are coupled in time domain through iteration method. Model tests of solid and liquid vessels in waves are conducted to validate the feasibility of the program. The coupling mechanism of liquid loading vessel is studied based on numerical and experimental results, and effects of liquid tank arrangement on vessel's responses are discussed. It is found that vessel's sway and roll motions are significantly affected by liquid sloshing in tank, while heave motion is slightly affected; the change of tank width can reduced the wave elevation caused by roll motion, and sway motion excited sloshing properties is mainly related to the natural sloshing frequency; the vertical position of liquid tank only affects the coupling effects of sloshing with roll motion mode and has no influences on coupling with sway motion mode. © 2019, Shanghai Jiao Tong University Press. All right reserved.