Theory of multi-diffusion flames
A theory which provides categorical classification and prediction of flame configurations for multi-component mixtures consisting of N species has been developed. The application of the theory of irreducible operators decouples the species equations; and the fundamental solutions, if they exist, satisfy the same equations as that of a binary mixture. The theory is applied to two flow configurations: first, the flame at the mouth of a tube in a duct, and second, the flame in an unconfined jet. The single mode flame structure is essentially the same as that of binary diffusion approximation with proper modification of the effective diffusivity. The double mode structure consists of two diffusion modes. The individual mode satisfies the diffusion equation with characteristic effective diffusivity. The theory could be easily used by experiments and designers for practical purposes such as correlating experimental data or estimating burner size.