Numerical Modelling of Fast Flames in Tubes

Numerical simulation of the unsteady propagation of very fast flames in an obstacle filled tube by means of a commercially available CFD code is presented here. Sensitivity analysis has been performed to assess the combustion rate parameters. The numerical predictions of the fully developed flame speed for methane-, propane- and hydrogen-air mixtures at different equivalence ratios have been compared with available experimental data. Good prediction was obtained in case of the development of fast deflagrations whereas the occurrence of the transition to the detonation regime was never predicted. A modified Eddy-Break-Up model has been introduced in order to improve the prediction of the transient phenomenon from the slow deflagration regime to the fast turbulent regime.