Mixing and Explosion Process of Propane-Air at Lower Flammable Limit in Confined Vessel

Propane is one of the major constituents in petroleum gas, and its concentration distribution and flammability in the air is the basis of safety measures for petroleum gas.The influence of concentration distribution on the flammability of the propane-air mixture was analyzed using numerical simulation and experiment.The FLUENT, a computational fluid dynamics (CFD) software, was adopted to simulate the three-dimensional gas mixing process and the combustion process at a low flammability limit in non-adiabatic vessels with length-to-diameter ratios (L/D) of 1, 3, 5 and 7, respectively.The results show that the concentration distribution of the propane-air mixture is inhomogeneous by gravity, and the concentration distribution is the prime cause of the spark location affecting the combustion behavior of the propane-air at a low flammability limit.With the increase of the length-to-diameter ratio, the peak overpressure decreases.