Ignition and Wind Effects on the Transition to Flame Spread in a Microgravity Environment

The fundamental processes involved in ignition and flame spread have been extensively studied, they are generally studied separately without combining ignition and flame spread through the transition process. Moreover, the majority of the flame spread studies assume steady state flame spread. To study the transient aspects of ignition and the transition to flame spread, a time-dependent numerical model has been developed in which a thin strip is ignited along its width with either a pilot wire, radiative source, or both. For this configuration, the model is two-dimensional. Ignition is initiated away from either end of the sample, and two different flame fronts spread in opposite directions; one flows with and the other against a prescribed external flow. Usually, the flame spread is initiated by ignition at one end of the sample with or against a slow external flow, yielding one flame front. The present configuration is more realistic than the one flame front case because there is interaction between the two flames during the ignition and transition stages.