Research On The Effects Of Crude Oil Tank Sloshing On Roll And Sway Motions Of FPSO

The Floating Production Storage and Offloading(FPSO)is an important equipment for the exploitation of offshore oil and gas resources at home and abroad.There are several large-volume tanks in a FPSO.Under the action of wind and waves,the FPSO undergoes a large motion,causing the sloshing of the crude oil tank.In turn,the sloshing effect can influence the motion of the ship and bring certain safety hazards.Therefore,this paper considers the sloshing of FPSO crude oil tank,analyzes the effects of sloshing on motions of FPSO,and reveals the influence mechanism.Based on the Computational Fluid Dynamics(CFD)method,the sensitivity factors of the sloshing dynamic characteristics of the tank are analyzed by Fluent software.Using the VOF two-phase flow model,the UDF method is used to define the forced movement of the tank.The sloshing moment acting on the wall and the dynamic pressure at the monitoring point are calculated.Comparing the data,the influence of the viscosity and density of the fluid on the sloshing dynamic characteristics is analyzed.The influence degree and mechanism of tank sloshing on the roll and sway motions of FPSO are analyzed.The analysis model of single crude oil tank is established.The amplitude-frequency response function of FPSO is calculated by Hydro D module of SESAM.The calculation considers different wave directions and analyzes the influence of wave directions on the coupling of tank sloshing and ship motions.The roll and sway motions of a ship-shaped FPSO in the South China Sea are calculated,considering the coupling effect of tank sloshing and ship motion.The calculation considers different wave directions and different liquid carrying rates.In this paper,the influence of the presence of transverse bulkhead,longitudinal bulkhead and the density of liquid in the tank on the coupling of tank sloshing and roll motion of the ship is studied.Based on a large number of analysis and research work,the influence of the viscosity and density of the fluid on the sloshing dynamic characteristics and the influence mechanism of a tank sloshing on the roll motion and sway motion are obtained,and the dangerous liquid carrying rate of the FPSO in this paper is calculated.The effects of transverse bulkhead and longitudinal bulkhead in the coupling of tank sloshing and ship motion are obtained.This paper obtains the effects on the coupling of tank sloshing and ship motion when the liquid density in the tank changes within the range of common crude oil density.The work of this paper has important research significance and engineering value for ensuring the safety of FPSO and the effective control of the adverse effects of tank sloshing.