Calculations of explosion deflagrating flames using a dynamic flame surface density model

Explosion deflagrating flames in a small scale vented chamber, with repeated obstacles are simulated using the large eddy simulation (LES) technique for turbulent reacting flows. A novel dynamic flame surface density (DFSD) combustion model, based on the laminar flamelet concept has been used to account for the mean chemical reaction rate. All cases considered here start with a stagnant, stoichiometric propane/air mixture. Three configurations with two baffle plates and a solid square obstacle, at different axial locations from the bottom ignition centre are examined. Numerical calculations of explosion generated pressure histories; flame characteristics such as structure, position, speed and acceleration are validated against published experimental data. Influence of the relative position of baffles plates with respect to the origin of the ignition are examined and discussed. Qualitative comparisons of the computed reaction rate are also made with images of laser-induced fluorescence from OH measurements. Good agreement obtained between numerical predictions and experimental measurements confirms the applicability of the newly developed dynamic model to predict the dynamics of explosion deflagrating flames.

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