Experimental research on thermal stratification of liquefied gas in tanks under external thermal attack

摘要

When liquefied gas tanks are exposed to fire, the temperature and pressure in tanks will increase and may cause boiling liquid expanding vapor explosion (BLEVE). According to relevant researches, the likelihood and the severity of BLEVE's hazards are significantly affected by the thermal stratification of liquefied gas. In this research, a device was set up to simulate the thermal response of liquefied gas tank under external thermal attack. In the tests two funiform electric heaters were used to simulate the fire, and a small steel vessel was used to simulate the tank, and the liquefied gas was simulated by water. The fill level, the heater power and the heated area were adjusted in the tests to simulate different accident conditions. The results showed that the liquid temperature is nearly uniform when the liquid space wall was heated solely; however, the temperature stratification was obvious when the liquid and vapor space walls were heated simultaneously. Based on the experimental results, this paper discusses how the temperature stratification appears and fades away.