论文总字数：31519字

摘 要

中国对液化天然气（LNG）需求不断扩大，同时液化天然气的储存设施未完全配套，出现了液化天然气供不应求的局面，因此中国加快了基础设施的建设工作。随着LNG储罐的不断增多，其发生泄漏的可能性也不断增大。天然气属于易燃易爆气体，当LNG发生泄漏时具有非常大的危险性。而水幕已被证实对重气云团具有良好的阻隔与稀释作用。为了研究水幕应用于LNG储罐泄漏扩散的防护效果，通过实验对水幕与泄漏口之间的距离、水幕高度、喷嘴类型和环境风速等参数对水幕防护效果的影响，并得出水幕防护系统的最佳参数。

实验结果表明：水幕高度是蒸气云高度的三倍以上防护效果更佳。水幕从更高处落下具有更大的动量，周围环境空气形成向上的气流将云团抬起，进而改变蒸气云团的扩散路径；水幕与泄漏源距离不宜太近，实验中0.35m的距离即可使水幕产生良好的稀释效果；锥形水幕由于自身喷射角度较小的限制，造成喷嘴间的空隙较大，对大面积蒸气云团的扩散抑制效果并没有扇形水幕好；风速达到1.0m/s时，环境风透过水幕，与水幕机械效应产生的气流相遇后在水幕内部形成空气湍流，加快泄漏口处形成的蒸气云扩散，向外扩散的蒸气云被气流扰乱稀释，密度减小的蒸气云在空气湍流作用下向上漂浮扩散，阻止了重气云沿地面扩散的趋势。通过实验结果得出最佳的水幕形式，并在此基础上设计LNG储罐最优效果的水幕防护系统。

关键词：水幕；液化天然气；储罐泄漏；防护系统

The Design of water curtain protection system for

LNG storage tank leakage

Abstract

China has stepped up infrastructure construction as its demand for liquefied natural gas (LNG) continues to grow and its storage facilities were not fully equipped. With the increase of LNG storage tanks, the possibility of LNG leakage increases. Natural gas is a flammable and explosive gas, storage tanks are dangerous when they leak. And the water curtain had been proven to have good barrier and dilution effects on heavy gas clouds. In order to study the effect of water curtain on the leakage and diffusion of LNG storage tank, the distance between the water curtain and the leakage source, the height of the water curtain, the nozzle type of the water curtain and the ambient wind speed were carried out. The optimal parameters of the water curtain protection system are obtained through experiments..

The results show that protection effect is better when water curtain height is more than three times the height of the steam cloud. The water curtain falls from a higher height with greater momentum, and the ambient air forms an upward airflow that lifts the cloud and changes the diffusion path of the vapor cloud. The water curtain should not be too close to the leakage source. The distance of 0.35 m in the experiment could make the water curtain produce good dilution effect. The conical water curtain has a large gap between nozzles due to its small injection angle, and the diffusion inhibition effect on large area vapor cloud is not as good as that of fan-shaped water curtain. When wind speed reached 1.0 m/s, the ambient wind passes through the water curtain, ambient wind passed through the water curtain and met the airflow generated by the water curtain to form an air turbulence inside the water curtain, accelerated the diffusion of the vapor cloud at the leak opening ,and outward spreading vapor clouds was disturbed and diluted by the current, and densified vapor clouds floated and diffused upward under the action of air turbulence, prevented the spread of heavy gas clouds along the ground. The optimal water curtain form was obtained through experiments, and the best water curtain protection system of LNG storage tank was designed on this basis.

Keywords: Water Curtain; Liquefied Natural Gas; Tank Leakage; Protection System

目 录

第一章 前言 1

1.1 研究的背景 1

1.2 研究的意义 1

1.3 国内外研究现状 2

1.3.1实验研究 2

1.3.2 数值模拟研究 3

1.3.3 存在的问题 4

1.4 本文主要研究内容 4

1.5 本章小结 5

参考文献 5

第二章 液化天然气储罐泄漏扩散抑制机理 8

2.1 液化天然气的性质 8

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