LNG双燃料大型汽车滚装船液舱晃荡与船舶运动耦合分析

Coupling Analysis of Liquid Tank Swinging and Ship Motion of LNG Double-fuel PCTC

液舱晃荡对船舶运动产生的影响不可忽略,晃荡引起的载荷与效应己成为航行中载液船舶安全性评估的重要内容之一。文章以7500 PCTC双燃料汽车滚装船为研究对象,分析LNG液舱在不同工况下液舱流体晃荡与船体运动耦合关系分。在频域中,利用三维水动力学软件求解船舶以及液舱的水动力方程,获得船舶与液舱的频域耦合运动频域特性,由IRF法得到时域波浪辐射力,计算船舶的水动力系数以及波浪载荷时域特性。同时基于VOF法模拟液舱晃荡,求解船舶与液舱晃荡耦合运动的时域方程。研究分析表明,液舱内液体的粘性对耦合作用有较大影响,特典型工况下,船舶的横摇和艏摇运动响应均减小,液舱总体起到了减摇舱的作用。

The influence of liquid tank sloshing on ship motion cannot be ignored.The load and effect caused by sloshing has become one of the important contents of the safety assessment of carrier liquid ship.In this article,the 7500 PCTC double fuel vehicle ro-ship is taken as the research object,and analyzes the coupling relationship of LNG liquid tank between liquid tank fluid sloshing and ship motion under different working conditions.In the frequency domain,the three-dimensional hydrodynamic software is used to solve the hydrodynamic equations of ships and liquid tanks,and the frequency-domain coupled motion characteristics of ships and liquid tanks are obtained.The time-domain wave radiation force is obtained by IRF method to calculate the hydrodynamic coefficient and wave load time-domain characteristics of ships.At the same time,it based on the VOF method simulating the liquid tank sloshing to solve the time domain equation of coupled motion of ship and liquid tank sloshing.The research analysis shows that the viscosity of the liquid in the liquid tank has a great influence on the coupling effect.The rolling and forward motion of the ships responses are both reduced under typical working conditions,and the liquid tank plays a role of anti-rolling tank on the whole.