Concentration and temperature profiles for cooland second-stage diethyl ether-air flames: Their Use in the Estimation of the Over-all Reaction Rate of Each Speciesand the Selection of a Satisfactory Combustion and Transition Mechanism

Abstract

A detailed VPC analysis of the various stable species encountered in the cool and secondstageflames of diethyl ether-air mixtures has led us to calculate their over-all appearance and disappearance rates. A comparison has been drawn between possible mechanisms and experimental data. Acetaldehyde appears to be the main product of cool-flame combustion, the process being of the branched-chain degenerate type in which hydroxyl radicals act as chain carriers. Second-stage flames are characterized by two chain carriers, namely OH radicals andhydrogen atoms. The study of the disappearance rates of these two species leads to distinguishing two steps. Acetaldehyde and methanol produced by the cool flame are consumed first, whereas the light hydrocarbons produced during the cool flame and during the first step are attaked by OH radicals and H atoms in a later step. The relative importance of these two steps depends on the initial composition of the flammable mixture.