Effects Of Confined Space Flow Fields On Explosion And Hazard Analysis

In this paper, FLUENT was used to simulate the effect of inlet velocity on the flow field of a spherical closed device, a gas explosion under different gas flow field conditions in a spherical explosive device, and the gas explosion incident in the Babao coal mine goaf. Results suggest that when gas is not evenly mixed, high local pressure occurs and the reaction is unstable. Time taken for the reaction to reach a maximum pressure under uniform mixing is generally shorter than that under non-uniform mixing, and maximum temperature and pressures are typically higher than those under the condition of uniform mixing. Residual CH4 after the simulated explosion reaction under non-uniform mixing increases with an increase in CH4 concentration. Higher ignition energy levels also result in the maximum explosion pressure being closer to the constant volume explosion pressure. Higher initial temperature results in a smaller maximum explosion pressure, and higher initial pressure results in higher maximum explosion pressure and temperature. Findings from the Baboa coal mine indicate that greater air leakage speeds resulted in a larger air leakage area in the goaf; the area of the low concentration gas distribution area was proportional to the air leakage speed. As air leakage leads to a decrease in gas concentration and an uneven distribution of mixed gas in the goaf, providing the precondition for combustion and explosion, it also expanded the intensity and propagation range of the gas explosion, potentially accounting for casualties recorded in the Babao coal mine goaf incident.