Ignition of a Pyrolyzing Solid with Radiatively Active Fuel Vapor

摘要

In this study the gas phase ignition model of a pyrolyzing combustible solid has been proposed in a one-dimensional slab geometry when it is initially exposed to a radiatively active high-temperature source. Only the pyrolysis product was assumed to abosrb and emit the radiation in the model. By applying it to the combustible polymethylmethacrylate (PMMA), the effect of radiation on the thermal history and ensuing ignition delay has been determined. The thermally radiative heating was found to be more influential than the conductive heating for activating PMMA ignition. An experimental observation of the temperature decrease (as being away from the fuel surface) in the radiant ignition of PMMA was also confirmed in this theoretical study. Whereas the emissivity of the hot source was observed to playa significant role in the ignition process, a change in distance between the fuel surface and the hot source made no appreciable change in the resulting ignition delay, because the radiation is predominant over conduction.