Motion and Sedimentation of Particles in Turbulent Atmospheric Flows above Sources of Heating

In this paper, theoretical investigation of the problem of particle evolution and sedimentation in turbulent gas flows above the zones of large-scale instabilities caused by heating from below is undertaken. The mathematical model takes into account the two-way coupling effects in gas-particle interactions and combines both deterministic and stochastic approaches. To simulate the gas-phase flow the k -epsilon model is used with accounts of the mass, momentum, and energy fluxes from the particulate phase. The equations of motion for particles take into consideration random turbulent pulsations in the gas flow. The mean characteristics of those pulsations are determined with the help of solutions obtained within the frames of the k -epsilon model. Contrary to the existing theories, the present approach enables us to take into account the polydispersed character of the mixtures. 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 particles influenced by both diffusive and kinetic characteristics. The obtained results make it possible to analyze the influence of inert and chemically reacting particles on the flow field induced by heating from below and by sedimentation and to determine the influence of sources of heat release on dispersion of particles and dynamics of the reaction zone.