Numerical simulation of premixed methane–air deflagration in a semi-confined obstructed chamber

•Deflagration in a semi-confined obstructed chamber is simulated using LES method.•Numerical results are in good agreement with published experimental data.•There is a positive feedback mechanism between flame propagation and flow field.•The pressure time history can be divided into four stages.•The mechanism of obstacle-induced deflagration is discussed.

In this paper, large eddy simulation coupled with a turbulent flame speed cloure (TFC) subgrid combustion model has been utilized to simulate premixed methane–air deflagration in a semi-confined chamber with three obstacles mounted inside.The computational results are in good agreement with published experimental data, including flame structures, pressure time history and flame speed. The attention is focused on the flame flow field interaction, pressure dynamics, as well as the mechanism of obstacle-induced deflagration. It is found that there is a positive feedback mechanism established between the flame propagation and the flow field. The pressure time history can be divided into four stages and the pseudo-combustion concept is proposed to explain the pressure oscillation phenomenon. The obstacle-induction mechanism includes direct effect and indirect effect, but do not always occur at the same time.