可燃固体颗粒堆中的逆向火焰传播

The flame propagation process in a pile of combustible particles was investigated in this study. The polymethyl methacrylate(PMMA)beads of 5mm in diameter were used as combustibles and O₂/N₂mixtures as oxidant. The flame propagation velocity and mass loss rate were measured under conditions with varying oxidant flow rate and oxygen concentration. It was found that oxygen flux was the dominant factor affecting flame propagation and mass loss. For a constant oxygen flux, increasing the flow velocity shortened the gas-phase preheating length of flame front, thereby reducing the flame propagation velocity. Meanwhile, the elongation of solid-phase preheating length led to an increase in mass loss rate. As a result, the flame propagation velocity and mass loss rate showed opposite change trends.