【作者】 胡建祥；

【导师】 马骏；

【作者基本信息】 大连理工大学 ， 船舶与海洋结构物设计制造， 2009， 硕士

【摘要】 液舱晃荡问题常常存在于装有液容器的运载工具或工程结构物中,例如船舶的液货舱、燃油舱以及海上储油罐等。随着石油开发力度的不断加大,出现了导管架储油平台等,因此,导管架储油平台的储油舱内也存在液体晃荡问题。当液舱的激励频率与舱内液体固有振动频率相近的时候,液体对舱壁结构产生强烈的冲击力,长时间作用会损坏舱壁结构。所以,液体晃荡载荷的分析及其对舱壁结构的作用成为导管架储油平台研发、设计时需考虑的问题之一。晃荡问题是非常复杂的液体流动现象,它具有很强的非线性和随机性特征,是典型的流固耦合问题。影响晃荡的因素很多,如:液舱的形状及尺寸、内部构件、液体装载率、液体属性等。本文研究的主要内容是通过得到导管架储油平台在波浪中的响应,以此作为激励,运用LS-DYNA程序,对导管架储油平台的储油舱液体晃荡情况进行仿真模拟,并讨论了不同装载率、不同激励频率等对液体晃荡的影响,主要工作内容如下:首先,本文阐述了研究晃荡的三种方法,并讨论了它们的优缺点,从流体运动方式的描述、控制方程的离散以及自由液面的追踪这三个方面详细阐述了数值模拟方法的原理。重点讨论了基于有限差分法的晃荡分析的原理、步骤及响应的特点。其次,阐述了利用半经验半理论的莫里森方程及Airy线性波理论推导出线性化波浪力力谱,然后通过动力响应分析得到导管架储油平台的最大位移响应,以此作为晃荡数值模拟的激励条件。最后,利用LS-DYNA分析了导管架储油平台液舱不同装载率水平下的晃荡,得到了晃荡动压力时程曲线、流体表面速度矢量图及自由表面波动图,讨论了不同的激励频率对晃荡的影响;并分析了晃荡动压力及温度对舱壁结构的作用,得到了晃荡应力及温度应力的量级。更多还原

【Abstract】 Liquid tank sloshing is often existed in vehicles and structures which are equipped with liquid containers, such as the liquid cargo tanks, fuel oil tanks and the ocean oil storage tanks. For the reason of the oil drilling developed rapidly, there are more and more oil storage jacket platforms, which also have liquid sloshing problems in the oil storage tanks. When the excitation frequency of liquid container closes to the nature frequency of liquid, the liquid produces intense impulse forces to the bulkhead structure and even damages to the structure by the long time action. Therefore, the liquid tank sloshing load analysis and its effect to the hull structure is one of the problems to take into account in the research and design of the oil storage jacket.Sloshing is a very complex phenomenon of flow with a high degree of nonlinearity and randomness, and is a typical problem of fluid and structure coupling. The intensity of sloshing depends on many factors, such as compartment forms, internal components, filling radios, liquid properties and so on. The main contents of this paper is to first calculate the oil storage jacket platform response to waves, and then simulate sloshing phenomenon of the oil jacket platform based on this stimulation by use of LS-DYNA, and then discuss the effect of sloshing due to different filling ratios, different excitation frequencies and different forms of the internal tank structure. The main works of this paper are as following:Firstly, introduced three basic methods of liquid sloshing study, and discussed their advantages and disadvantages. Elaborated the principal of numerical simulation from the description of fluid movement, the dispersal of control equations and the tracking of free surface. The discussion focuses on the principal steps and related characteristics of the sloshing analysis based on the finite difference method.Secondly, introduced the spectrum of linear wave force deduced through semi-theoretical semi-empirical formula of Morison and Airy wave theory, and obtained the maximum displacement response through dynamic response analysis of the oil storage jacket platform as the excitation in the numerical simulation of sloshing.Finally, analyzed the sloshing load under different filling ratios by the use of LS-DYNA and obtained sloshing dynamic pressure time history curve, velocity vector of fluid surface and the free surface fluctuation. Then the paper discussed the effect of sloshing due to different excitation frequencies. What’s more, the sloshing dynamic pressure and temperature effect caused to hull structure is considered and the sloshing and temperature stress magnitude is obtained.更多还原