摘要:随着航运业的不断发展,油船破舱溢油事故造成的严重环境污染和巨大经济损失越来越受到社会关注。为了减小泄漏灾害产生的影响,必须从防止泄漏和控制溢油两方面着眼,提出切实可行的应急方案。而达到此目的的前提是建立能够预测漏油轨迹,确定泄漏总量、泄漏速度和泄漏总时间的破损液舱泄漏预报数学模型。
本文为了模拟真实条件下具有自由液面、互不相溶的油-水-气三相流动,基于Ansys15.0软件利用流体力学计算软件FLUENT,采用有限体积法(VOF)和k-ε模型建立二维油船液舱的三相流模型,动态模拟油舱破孔后油品在静水中的泄漏行为。然后基于主动吸收推板造波和能量源消波的原理,借助FLUENT软件中的UDF功能,建立二维线性数值波浪水槽模型,动态模拟波浪作用下破舱漏油的特征。根据以往油船水下边舱破损导致的泄漏事故的经验,设计破孔位置和大小,并且分别设计单壳和双壳模型。通过对整个溢油漂移扩散过程进行分阶段的特征分析,可以得出不同破孔形式,液舱单、双壳结构的不同设计以及舱体液面内外高度差对泄漏的影响。从而可以分析得到有效阻止和控制泄漏的方法和机理。
关键词:溢油模型;数值模拟;波浪水槽;阻漏
Abstract:With the development of the shipping industry, it draws more and more attention that the oil-spilling accidents contribute a great amount of pollution to the environment and cause tremendous economic loss. In order to make the quick emergency response when such incidents happen, a precise and practical numerical model has to be developed, considering preventing and controlling oil leakage. Only when we are able to predict the spill trajectory, the spill time, the oil leaking speed as well as the total spill volume can we achieve this goal.
The real-world flow has free surface and multiphase, which is consisted of oil, air and water. The three phases are not mutually soluble. The realizable k-ε turbulence model is carried out in the FLUENT software to simulate the oil leakage from the puncture in the side of the cargo tank after collision accidents. The Volume of Fluid (VOF) model is employed to solve the nonlinear free surface. After that, a two-dimensional numerical
linear wave flume is developed through the UDF(user defined function)in FLUENT code,
utilizing the piston-type wave-making method and source absorbing method. The oil spill under the wave then can be investigated. Based on the past experience, different sizes of the puncture, different positions of the hole are designed to be studied. Also, the simulation verifies that the double-hull design has a good performance on retaining the oil. By analyzing the quantitative information represented by the simulation results, some conclusions about the how to control and reduce the oil spill are drawn.
Keywords:Oil Spill Model; Wave flume; Numerical simulation; Spill prevention
目 录
第一章 绪论 1
1.1课题的研究意义和应用前景 1
1.3本文主要工作 3
第二章 数学模型及数值解法 5
2.1数学模型 5
2.1.1质量守恒方程 5
2.1.2动量守恒方程 5
2.1.3能量守恒方程 6
2.1.4初始条件 6
2.1.5边界条件