Influence of thermal stratification by fire on heat-mass coupling response mechanism of the liquefied tank

Abstract

In order to study the explosion-inducing process and thermal response of fire-induced BLEVE(boiling liquid expanding vapor explosion), a small experimental device was established. The radiant heating source was used to simulate the external fire heat effect, and superheated water was used as the medium. The pneumatic ball valve was used to simulate the leakage action. The gas-liquid flow, internal pressure and temperature transient response of the tank during the heating and venting processes were measured, and the superheated process of the medium in the tank was analyzed. The temperature-pressure coupling response after the explosion was traced to investigate the thermal action of the fire on the tank. The experiment found that the heating of the storage tank was the generation and gradual disappearance of temperature stratification. The crack action would result in the breaking of phase equilibrium and pressure rebound. There was an overheat delay in the detonation, and the temperature stratification would prolong the overheat time of the medium. There was a lower limit for the occurrence of the BLEVE accident, the critical stratification degree was used to quantify the limit and the limit of this experimental condition was ξ≤2.33.