LES of flame acceleration and DDT in small-scale channels

Large eddy simulation (LES) has been performed to investigate the process of flame acceleration (FA) and deflagration-to-detonation transition (DDT) in a small-scale channel filled with methane-oxygen mixture. A transport model for sub-grid kinetic energy was used to enclose the sub-grid fluxes while the sub-grid scale combustion was modeled by the artificially thickened flame (ATF) model. A fifth-order Weighted Essential Non-oscillatory (WENO) finite difference scheme was used to discretize the advection term of the governing equations. The results showed that the interaction of the flame with the flow and the pressure wave ahead led to the flame acceleration. The overdriven detonation led by the local explosion formed and the flame propagated upstream which then coupled with the precursor shock wave. A retonation wave propagating downstream was further observed. The experimental results substantiate the validation of the calculation and further identified the DDT mechanism.