Ignition and combustion of turbulized dust-air mixtures

A mathematical model for turbulent combustion and ignition of polydispersed dust-air mixtures is developed. The worked out mathematical model takes into account the two-way coupling effects in gas-particles interactions and combines both deterministic and stochastic approaches. The equations of motion for particles take into consideration the influence of random turbulent pulsations in the gas flow. The models for phase transitions and chemical reactions take into account thermal destruction of dust particles, vent of volatiles, chemical reactions in the gas phase, and heterogeneous oxidation of carbon by O-2 and CO2 influenced by both diffusive and kinetic characteristics. The model is validated in comparison with experiments on organic dust combustion in confined volumes, under different levels of initial turbulization of the mixture. The developed mathematical model makes it possible to investigate the peculiarities of polydispersed organic dusts ignition and combustion and the influence of flow nonuniformities on the ignition limits. (C) 2000 by The Combustion Institute.