Updated asymptotic structure of cool diffusion flames

The influence of adding a seventh important elementary step to a six-step mechanism, previously employed for describing the asymptotic structure of normal-alkane droplet combustion supported by cool-flame chemistry in the negative-temperature-coefficient (NTC) range, is investigated by analytical methods. A development paralleling the classical activation-energy-asymptotic (AEA) analysis of the partial-burning regime, accompanied for the first time by an AEA analysis for a negative activation energy, to account properly for the removal of an important intermediate species, is pursued to make predictions of the combustion process, resulting in a revised asymptotic structure that agrees better with computational predictions based on detailed chemistry.