LNG船泄漏事故液池扩展计算及不确定性分析

Pool Spread Calculation of LNG Carrier Spills and Uncertainty Analysis

根据小孔射流、惯性-质量平衡扩展等理论搭建包括泄漏源强和液池半径扩展在内的LNG船泄漏液池扩展模型,分析影响液池扩展变化的重要参数及其不确定性,借助MATLAB编程计算这些不确定对预测结果的影响。研究结果表明:导致LNG船泄漏的事件不同,泄漏口的大小可能会有所不同(0~16 m^2不等),当泄漏口面积<2m^2时,液池扩展对泄漏口大小的变化相当敏感;受泄漏口形状和流动状态等因素影响,流量系数取值范围较广(0.4~1.0),预测偏差可达2.5倍;因LNG-水搅合程度及沸腾形式不同,液池蒸发速率为0.042~0.25 kg/(m^2·s),预测的最大液池半径差别较大。

A model for pool spread of LNG carrier spills is proposed based on the theory of orifice flow and inertia-gravity balance. The uncertainties of important parameters are analyzed, and the degree of the impacts of them on predicting results is calculated by means of the software MATLAB. The research reveals the following facts ： Different kind of accidents （ collision, grounding or terrorist attack） may result different LNG carrier leakage and the possible breach size can vary from 0 to 16 m2 ; The pool spread is sensitive to the breach size when it is less than 2 m2 ; The discharge coefficient, which is dependent on the breach shape and the liquid property, varies significantly, and the prediction deviation can be great, possibly up to 250% ; The average evaporation rates also show wide variations （0.042 -0.25 kg/（ m2 · s） ） depending on the effects of the LNG-water turbulence and the boiling region.