Modeling the behavior of LPG tanks exposed to partially engulfing pool fires

Accident scenarios leading to full or partial fire engulfment represent a serious threat to tanks used for the transportation and storage of dangerous goods. The present study focuses on the impact of partial engulfing fire scenarios on an LPG tank. An experimentally validated CFD modeling approach was further developed and applied to perform a parametric study by varying the exposure mode and the filling degree. The results of the simulations show that both these factors have a strong influence on the pressurization rate, the energy accumulation, and the high-temperature mechanical weakening of the tank structure. Fire scenarios where the flame zone is at the top or at the end of the tank are particularly critical when the liquid filling degree is low or medium. Liquid thermal stratification is evident in all the case studies analyzed and, in most of them, it strongly affects the vessel pressurization curve. The comparison to the results obtained using a lumped model showed that this provides non-conservative pressurization results for high filling levels (80%). The results show that a validated CFD approach can be used as a virtual workbench to support tank design within a digital twinning approach.