A comparative experimental study of flames propagating in mixtures of oxygen with methyl alcohol, formaldehyde or formic acid has been made. The results have been compared with those obtained in a previous work on methane-oxygen flames and show a remarkable similarity. A kinetic interpretation is proposed.
Although methane and its partial oxidation products differ markedly in their behaviour when they are submitted to a slow reaction with oxygen in the gas phase, the experimental results presented in this paper show a remarkable analogy between the burning velocities of the flames propagating in the mixtures of any of these compounds with oxygen, provided the amount of diluent is adjusted in such a manner as to render the flame temperatures identical. As it will be discussed in the last section of this paper the observed analogy finds its explanation in the fact that the branching process happens to be the same, even if some differences occur in the mechanism of the chain reaction by which the fuel molecules are transformed into complete oxidation products. (*) This research has been sponsored in part by the AIR FORCE OFFICE OF SCIENTIFIC RESEARCH through the EUROPEAN OFFICE OF AEROSPACE RESEARCH (OAR), UNITED STATES AIR FORCE, under Grant AF-EOAR-66-44.