Ignition of pyrophoric powders: An entry-level model

30th International Conference on Interaction of Intense Energy Fluxes with Matter

Alymov, M.I.^1 ; Seplyarskii, B.S.^1 ; Gordopolova, I.S.^1

Institute of Structural Macrokinetics and Materials Science, Russian Academy of Sciences, Academician Osipyan 8, Chernogolovka, Moscow Region

142432, Russia^1

关键词: Approximate methods;    Combustion theory;    Critical condition;    Fine dispersed powders;    Ignition process;    Pyrophoric powders;    Specific surface;    Spontaneous self-ignition;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/653/1/012052/pdf
DOI  :  10.1088/1742-6596/653/1/012052

来源: IOP

【 摘 要 】

Chemically prepared metal nanopowders are normally pyrophoric, i.e. are liable to ignite spontaneously on exposure to air because of high reactivity and developed specific surface. On the other side, reliable theoretical models for spontaneous self-ignition of fine dispersed powders at room temperature have not been suggested so far. A deeper insight into the mechanism of the phenomenon would shed new light on the critical conditions for self-inflammation and thus would provide some clues for optimization of the passivation of fine dispersed powders. In this work, we formulated and analyzed an entry-level model for ignition of pyrophoric powders. Analysis of such a model in terms of the ignition theory gave the following results. Depending on the width of the reaction zone, the ignition may get started in either one or two stages. The duration of each stage was evaluated by using the approximate methods of combustion theory. The parametric limits for the model applicability were derived and the influence of sample length on the ignition process was explored as well.