Numerical Simulation of Evaporative Gas Behavior Inside Fuel Tank During Fire Extinguishing Process

A series of explosions at a domestic business site injured approximately 20 people, and joint analysis revealed substandard fuel at the site. The first explosion was caused by the ignition of oil vapor released from the fuel tank, and the second had likely occurred when an ignition source entered the tank. This study models the secondary explosion using a fire dynamics simulator, with acetone and dodecane adopted as representative fuels. The results show that acetone exceeds the upper explosive limit under external heating, whereas it re-enters the flammable range upon cooling, thereby increasing the explosion risk if ignited. By contrast, dodecane does not re-enter the flammable range under the same criteria.