喷射水幕对LNG蒸气扩散影响的CFD模拟

在液化天然气（LNG）站场内设置喷射水幕是安全隔离、控制LNG泄漏后蒸汽云扩散和减缓事故后果的重要措施之一，然而目前对各类型水幕的减缓效果进行数值分析的成果鲜见。为此，利用计算流体力学（CFD）模型以及事故场景建模和动态模拟的方法，分别对扇形和锥形喷射水幕的下风向蒸气云扩散的穿透过程和阻隔性能进行设置模拟和参数分析，研究了不同水流量、水幕与扩散源间距等参数对减缓性能的影响情况。结果表明：①合理设置水幕能够将扩散安全距离减小50%以上，危害面积减小60%以上；②在同样的水幕喷射压力和喷射流量下，扇形水幕的阻碍效果优于锥形水幕；③提高喷射压力、增加水幕高度和宽度、合理设置水幕和泄漏源间距，均有利于降低蒸气云扩散距离，有效增强被保护设施的安全性。

CFD simulation of water spray curtain application in dispersing liquefied natural gas vapor clouds

In an LNG terminal, water spray curtain, as one of the most important mitigation methods, is applied to eliminate the hazard of LNG vapor cloud dispersion for safety concern. However, little attention has ever been paid to numerical studies on such hazard eliminating effects of different types of water spray curtain. In this paper, Computational Fluid Dynamics (CFD) was applied to establish time dependent models of different accident scenarios, including the LNG vapor cloud penetrating process and curtain blocking effects of cone curtain and flat fan curtain. Parameters of water flow rate and spacing distance between the curtain and dispersion source were investigated. The results show that a. reasonable layout of spray water curtain can reduce the dispersion exclusive distance by more than 50% and hazard area by more than 60%; b. upon the same water spray pressure and flow volume, the flat fan curtain works better than the cone one; and c. through increasing the water spray pressure and the size of water curtain, and setting a proper distance between dispersion source and curtain, the hazard affecting the area by the LNG vapor cloud dispersion can be decreased. This study provides theoretical basis and reference for the water spray curtain design in an LNG terminal or an LNG plant.