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6232041 
Journal Article 
A shock tube study of ignition of methane-oxygen mixtures 
Asaba, T; Hikita, T; Kakihara, N; Yoneda, K 
1963 
0 
Symposium (International) on Combustion
ISSN: 0082-0784 
9 
1 
193-200 
Ignition of methane-oxygen mixtures was studied by use of the shock tube. Data on ignition delay suggested that two different mechanisms exist, depending upon the methane content; first, for lean mixtures, the branching chain mechanism at relatively low temperatures governs the reaction during the induction period; and second, for rich mixtures, the thermal chain mechanism governs the reaction at high temperatures. For rich mixtures, the controlling reaction is considered to be the second order reaction between methane and oxygen with an activation energy of about 55 kcal. For lean mixtures, it is suggested the ignition is of the branching chain type and the activation energy is found to be about 21 kcal In discussing the branching chain mechanism, oxygen atoms are considered to be important chain carriers. As the concentration of methane increases, methane molecules deactivate oxygen atoms. This may be the reason why the branching chain reactions do not occur in the rich region.