Large eddy simulation and experimental study on vented gasoline-air mixture explosions in a semi-confined obstructed pipe

In this work, LES simulation coupled with a TFC sub-grid combustion model has been performed in a semi-confined pipe (L/D = 10, V = 10 L) in the presence of four hollow-square obstacles (BR = 49.8%) with circular hollow cross-section, in order to study the premixed gasoline-air mixture explosions. The comparisons between simulated results and experimental results have been conducted. It was found that the simulated results were in good agreement with experimental data in terms of flame structures, flame locations and overpressure time histories. Moreover, the interaction between flame propagation process and obstacles, overpressure dynamics were analyzed. In addition, the effects of initial gasoline vapor concentration (lean (ϕ = 1.3%), stoichiometric (ϕ = 1.7%) and rich (ϕ = 2.1%)), and the number of obstacles (from 1 to 4) were also investigated by experiments. Some of the experimental results have been compared with the literature data. It is found that the explosion parameters of gasoline-air mixtures (e.g. the maximum overpressure peaks, average overpressure growth rates, etc.) are different from some other fuels such as hydrogen, methane and LPG, etc.