Study On Sloshing Of Shipborne C-type Tank In LNG Carrier

As a large country of natural gas consumption,China is also a major importer of natural gas.Nearly 40% of natural gas needs to rely on imports and maintain a rapid increase.As an important transportation tool for natural gas,LNG carriers have become a major development trend.LNG carriers are subject to waves of different wave directions and frequencies during navigation,resulting in complex motion responses.Under the action of ship motion,the LNG cargo tank will slosh,and the violent sloshing pressure may bring huge safety hazards to the tank structure.Therefore,research on the sloshing pressure of LNG tanks has important engineering value.This paper uses AQWA and FLUENT software to study the motion response and tank sloshing of LNG carriers.The main contents are as follows:The calculation method of ship motion response in wave is expounded.The hydrodynamic calculation model of a ship is established by AQWA software,and its motion response is calculated.The results are compared with the existing experimental results.The feasibility of the calculation method used was verified.The hydrodynamic model of the LNG carrier is established,and the motion response of the LNG carrier is calculated.The motion response characteristics of the ship at different speeds and waves of different frequencies are obtained.The resonant frequency of the different degrees of freedom of the LNG ship and the relationship of the motion response with the speed are obtained.The VOF method in FLUENT software is introduced,and the tank sloshing experiment in the literature is simulated by FLUENT software.The results of the simulated pressure change with time and the liquid level change during the sloshing process are compared with the experimental results,The feasibility of the calculation method used was verified.The method is used to calculate the sloshing of the ship’s tank in the LNG carrier.The variation of the slamming pressure during the horizontal and vertical sloshing of the tank at different external excitation frequencies is analyzed.For the vertical sloshing of the tank,there is a significant natural frequency.When the sloshing frequency is close to its natural frequency,the slamming phenomenon is obvious.Analysis with the calculated vertical and horizontal yaw frequency and amplitude of the LNG carrier and the slamming pressure change law of the tank sloshing,find the possibility of the maximum slamming pressure,further comparison and calculation of these situations leads to conclusions.