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

Abstract

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.