Weak Burning and Gas-Phase Ignition about a Carbon Particle in an Oxidizing Atmosphere

Abstract

—The departure from frozen flow behavior about a carbon particle in an oxidizing atmosphere, has been discussed in order to obtain the burning rate M over a wide range of the Damköhler number D_g (representing either the particle size or the ambient pressure). The frozen limit (D_g →0) leads to values of M ranging up to M ₂, the maximum burning rate corresponding to diffusion controlled heterogeneous reactions. By contrast, for finite values of D_g we find that the burning rate is limited by M _lg<M ₂. The maximum Damköhler number D_g ° given by an explicit formula, corresponds to gas phase ignition.