Chemical Element Diffusion Factors for Use in the Conserved Scalar Approach to Diffusion Flame Modeling

摘要

A theoretical reacting flow model which considers the effects of finite-rate chemistry and composition- and temperature-dependent thermodynamic and transport properties was used to determine the velocity, temperature and species concentration profiles established in a laminar methane-air diffusion flame. The model was validated by comparison of calculated and experimentally obtained profiles. The calculated molecular species concentration profiles were used to determine those of the chemical element mass fractions. Dissimilarity in the distributions of normalized conserved scalars based on the C, H, O and N chemical elements mass fractions was used to illustrate the effect of differential species diffusion. Effective diffusion factors of the chemical elements were determined from the distributions of the molecular species. These effective elemental diffusion factors are independent of temperature, pressure and composition and allow the conserved scalar approach to diffusion flame modeling to be employed without the need to assume equal diffusion coefficients for all species. (ERA citation 06:005156)