MODELING OF COMBUSTION WAVE-PROPAGATION IN A CARBON DUST GAS-MIXTURE

Combustion wave propagation in a carbon dust/gas mixture is studied, t aking into account both radiative and conductive heat transfer. A two- temperature mathematical model is suggested for the analysis of the no nstationary processes occurring in exothermic reactions during propaga tion of the wave front in a carbon dust/gas mixture. Temperatures of t he particles and gas are assumed to be different and radiative heat tr ansfer is described by a diffusion approximation. Particle size is var ied in the range of 10 to 200 mu m In the absence of heat losses, tran sition from the slow conductive combustion to the fast radiative one i s explosive in nature. In such a case, both the combustion wave veloci ty and the width of the reaction zone are enhanced by 2-3 orders of ma gnitude. In the presence of heat losses, the behavior of the flame fro nt propagation is changed drastically. Conductive heat losses may resu lt in nonuniqueness of combustion. Depending on the initiation conditi ons, either a slow, or fast combustion wave may be expected to be gene rated in the system. Radiative heat losses lead to diminished combusti on wave velocities, and marginally, to the transition from fast to slo w combustion. Some aspects of pulsating combustion have also been cons idered, such as the oscillations of combustion wave velocity and parti cle and gas temperatures. Instability development is studied with the suggested model.