The Near-Stoichiometric Behavior of Combustible Mixtures Part II: Dissociation of the Products

Abstract

The burning rate of a combustible mixture is experimentally found to be maximum when the unburnt mixture is slightly fuel-rich. In Part I the authors explained this neat-stoichiometric behavior purely on the basis of diffusion of the reactants. The usual explanation is based on dissociation of the products, according to which dissociation causes the maximum flame temperature and therefore the maximum burning rate to occur slightly on the fuel-rich side of stoichiometry. However, as indicated in Part I, several aspects of this explanation are unsatisfactory. The purpose of the present paper is to show that while dissociation explains the shift of the maximum temperature onto the fuel-rich side, it has only a subsidiary effect on the maximum burning rate.