Ignition of methane/air mixtures with inert and reactive particles heated by radiation

This study utilizes a self-designed experimental apparatus to heat inert silicon carbide and reactive coal particles via thermal radiation in order to ignite methane-air mixtures. The objective of these ignition experiments is to determine the difference in ignition characteristics between inert and reactive particles. Therefore, a series of ignition experiments with varying types of particles, irradiances, particle sizes, and fuel mixture equivalence ratios were performed to determine the effects of these parameters on ignition time and ignition temperature. The results of the experiments indicate that ignition time and ignition temperature are both influenced by the fuel mixture equivalence ratio, particle type, and particle size, while irradiance only influences ignition time. Ignition temperature and time were observed to be higher and longer, respectively, for reactive particles than inert particles. Furthermore, ignition temperature is inversely proportional to particle size; while, ignition time is directly proportional to particle size and inversely proportional to irradiance. Chemical reaction of coal particles narrowed the flammability limit of the fuel mixtures, results in a longer time and higher ignition temperature, and causes a more powerful ignition than that of inert particles due to the possibility of secondary ignition.