Study on the characteristic of boiling expansion process of superheated LPG and its vapor cloud explosion

Liquefied Petroleum Gas (LPG) is stored in liquid form under high pressure conditions. Once the tank fails, LPG will leak in gaseous form hundreds of times its liquid volume. LPG inside the storage tank will undergo a violent boiling process leading to pressure rebound in the tank. In serious cases, boiling liquid expanding vapor explosion (BLEVE) will happen. And the leaking LPG will mix with air to form a flammable vapor cloud that can explode. Therefore, it is necessary to study the violent boiling process inside the LPG vessel after rupture, the leakage diffusion process in the surrounding environment and the vapor cloud explosion process. In this paper, CFD software FLUENT was used to conduct numerical simulation of the inter-phase transfer of mass and heat inside the vessel when LPG leakage happens, and the transient pressure inside the vessel was analyzed. The results obtained from the simulation are in good agreement with the experimental data under the same conditions which provides the validity verification of the phase transition during boiling process of LPG. A three-dimensional numerical model of LPG release process after the failure of a cylindrical vessel was established. The realizable k-ε model and eddy-dissipation model were used to simulate the explosion process of LPG after the release. The pressure, temperature and thermal radiation distribution of the explosion flow field were obtained so the damage range of LPG after explosion can be analyzed, which has certain guiding significance for the risk assessment of LPG.