Binary diffusion coefficients and non-premixed flames extinction of long-chain alkanes

Abstract

The current study aims to resolve the experimental and modeling discrepancies previously observed for the extinction strain rates of counterflow, non-premixed n-decane and n-dodecane/nitrogen mixture versus oxygen. To achieve this goal, a recently developed transport theory of cylindrical molecular structure in dilute gases is used to model the binary diffusion coefficients of long-chain n-alkanes up to n-dodecane in N2 and He. The updated diffusion coefficients are found to be significantly different from early estimates made from the law of corresponding states. The diffusion coefficient update removes the early difficulties in modeling the extinction strain rates for non-premixed extinction of n-decane and n-dodecane. It was found that the mixture averaged transport formulation can provide good predictions provided that the Soret effect on the transport of large fuel molecules is properly accounted for.