Large Eddy Simulation of transient premixed flame-vortex interactions in gas explosions

In this work, a Large Eddy Simulation (LES) model was used to simulate the transient premixed flame-vortex interaction, which is the key phenomenon determining dynamics and consequences of gas explosions. In particular, the effect of the grid resolution on the impact of the combustion sub-model was investigated. To this end, LES computations were run, with and without the combustion sub-model, on three non-uniform unstructured grids with cell characteristic length varying in the ranges 2-3. mm, 1-2. mm and 0.5-1. mm. Numerical predictions were compared with literature experimental data. It has been found that the amount of detail explicitly resolved on the finer grid (having a resolution of the same order of magnitude as the laminar flame thickness) is such that, even without the combustion sub-model, the LES results obtained with this grid correctly match the experimental data in both quantitative (flame speed and flow velocity) and qualitative (shape and structure of the flame front) terms. © 2011 Elsevier Ltd.