Diffusive and Radiative Transport in Fires Experiment: DARTFire

The physics of opposed-flow flame spread over solid fuels is reasonably well understood for the situation in which the incoming flow speed is much greater than the flame spread rate. The propagation process is dominated by forward conduction heat transfer, either through the gas or solid, and the gas-phase kinetics. The characteristics of the spread process can generally be divided into a thermal regime, i.e., a regime in which gas-phase kinetics can be considered infinitely-fast, the spread rate being dictated by conduction hear transfer, and a kinetic regime in which gas-phase chemical kinetics is important. For thin fuels in the thermal regime, the spread rate is independent of flow speed while for thick fuels it is proportional to the flow speed. In the kinetic regime, increases in flow speed cause a reduction in spread rate that eventually leads to flame extinction through flame blowoff.