基于MPS方法数值模拟三维LNG液舱的晃荡问题

该文基于自主开发的无网格粒子方法求解器MLParticle-SJTU,将MPS方法(moving particle semi-implicit)应用到三维LNG液舱的晃荡问题中,分别研究了LNG液舱在单自由度纵摇和横摇激励下,装载高度和激励频率对液舱晃荡作用的影响。首先,对装载高度为70%H的LNG液舱在单自由度纵摇和横摇激励下的晃荡问题分别进行了数值模拟,并将计算结果与实验结果进行比较,验证了MPS方法的可靠性。其次,对比不同装载高度,不同激励频率下液舱晃荡的拍击压力和流场分布情况,分析了装载高度和激励频率对晃荡作用的影响,并分析了一阶固有频率和共振频率随装载高度的变化规律。数值结果表明:激励频率对晃荡幅度影响较大;当激励频率在一阶固有频率附近时,会发生剧烈的晃荡现象;52.5%H为危险装载高度,在共振频率下,产生的拍击压力最大。

Numerical study on liquid sloshing in 3D LNG tank by MPS method

In this paper,our in-house meshfree particle method solver MLParticle-SJTU is applied to model 3D liquid sloshing in LNG tanks.The effect of filling level and excitation frequency on liquid sloshing,excited by SDOF rolling and SDOF pitching motion respectively,is parametrically investigated and discussed.Firstly,validation is performed with 70％H filling level by comparing the numerical results with the corresponding experimental data.The MLParticle-SJTU solver is proved to be reliable and efficient to solve 3D sloshing problem.In addition,liquid sloshing in LNG tanks excited by SDOF rolling and SDOF pitching motion is investigated to analyze the effect of the excitation frequency and filling level on the amplitude of sloshing.Results show that,sloshing is significantly affected by excitation period.Liquid sloshing is violent when the excitation frequency is around the model natural frequency.The filling level of 52.5％H is the most dangerous,the impact pressure reaches the maximum when the excitation frequency is the resonant frequency.