Flame Propagation in Closed Vessels and Flammability Limits

Abstract Abstract-Flame propagation in near-limit mixtures of ethylene and air has been investigated by using a spherical vessel. A model of the flame behavior in closed vessels has been formulated, which takes into account the complete motion equation and the heat losses by the flame to the surroundings. The model forecasts two possible mechanisms of flame failure: the "homogeneous" flame extinction due to the exchanges of the rising flame towards the unburned gases, and the "heterogeneous" extinction due to conductive heat losses to the walls after flame impingement on the vessel top. The theory and the experimental data fairly agree; in particular the dependence of the measured "heterogeneous" limit on the igniter position is explained.