Transport coupling theory for multicomponent nonequilibrium chemically reacting boundary layers

A general analysis of thermodynamic coupling effects in flames and other nonequilibrium gas‐phase chemically reacting multicomponent boundary‐layer flows is presented. Changes in characteristic diffusion time relative to characteristic reaction time due to thermal‐diffusion, diffusion‐thermo‐ and multicomponent‐diffusion effects are considered and a new generalized gas‐phase Damkohler number which encompasses these effects is defined. Using a transformed total enthalpy‐concentration field and the newly defined Damkohler number, compressible laminar reacting boundary layers were analyzed and compared with other available analyses for simpler specific cases. The applicability of the present theory is demonstrated by new solutions for the problem of combustion of injected premixed fuel. Comparison between these results and uncoupled solutions reported in the literature indicate that thermodynamic coupling effects are significant, especially when Damkohler numbers are smaller than unity.