Conductive–radiative model of a laminar flame in dust suspensions

A mathematical model is proposed to describe a laminar flame in gas suspensions with particles burning in the diffusion mode. Conductive and radiative heat transfer in the combustion wave and also the differences in temperatures and velocities of the solid and gas phases are taken into account. An analytical expression for the normal flame velocity as a function of the fuel and oxidizer concentrations and the particle size is derived. Theoretical predictions are demonstrated to agree well with experimental data on the flame velocity dependence on the particle size in suspensions of magnesium particles in air. The relative role of radiative heat transfer and sedimentation of particles in the suspension is analyzed.