RELATIVE INFLUENCES OF CONVECTIVE AND DIFFUSIVE TRANSPORTS DURING SPHERICAL FLAME INITIATION

A model of spherical flame initiation is discussed and studied numerically in the case of a central heat point source. Integrations of the corresponding balance equations are performed under the constant density approximation and in the actual situation involving a variable density. Thus, the relative influence of convective and diffusive transport is evidenced. In both cases the minimum ignition energy, as well as the characteristic size and time relative to the (external) energy-supported flame front evolution, are shown to the controlled by competition between heat conduction and limiting reactant diffusion. However, reproducing a detailed realistic flame front history requires the density variation to be taken into account.