Abstract:

A calculation methodology has been developed to simulate cryogenic liquid spilling from various tanks,pool spreading and mass transfer on water.The shallow water differential equations have been used to illustrate the spreading process in this methodology.Not only the maximum radius and life of the pool can be calculated,but also the height profile of the pool is able to be presented.This methodology has been applied to simulating 12500 m³ LNG(liquefied natural gas)spreading on water which were supposed to be released from breach holes on various tanks.The simulation results have been analyzed in three aspects.First,breach diameters show a Boltzmann nonlinear relation with pool radius.Second,through researching the pool shape and tank configuration,it is found that it is adoptable to substitute cubic tank for spherical tank and substitute semicircle pool for shape-changing pool for the scenario modeled in this article.Finally,the contrastive analysis between this model and the Federal Energy Regulatory Commission(FERC)model which is based on depth-averaged integral equations reveals that the averaged depth leads to a larger pool radius.

Key words: liquefied natural gas, spillage, spread, phase change, mass transfer, vaporization

摘要：

基于微分浅水方程对液化天然气(LNG)从不同类型的储罐中泄漏并在水面扩散的过程进行了模拟。通过低温液体扩散形成的液池的最大半径和生命周期对出流孔尺寸、液池形状和储罐形状进行了评估。对泄漏量为12500 m³的LNG泄漏过程的模拟计算表明,液池的最大半径与出流孔径表现出较好的Boltzmann非线性关系。对不同形状的液池和不同形状的储罐进行模拟分析表明,用半圆形液池来代替不断变化形状的液池和用立方体储罐简化球形储罐都是可取的。此外,模拟结果还与积分浅水模型的计算结果进行了对比,结果表明,基于平均深度的积分浅水模型相对于微分浅水模型会得出较大的液池半径。

关键词: 液化天然气, 泄漏, 扩散, 相变, 传质, 汽化