The Addition Effect of CH3Br and CH3Cl on Ignition of CH4 by Shock Wave

Abstract

Ignition delay times were measured in the CH4–CH3X (X: Cl or Br)–O2 system diluted in Ar using a shock tube. The times were shorter than those without CH3X, indicating that CH3X accelerates the ignition of CH4. A theoretical model including 8 elementary reactions concerning CH3X, with a CH4 oxidation mechanism consisting of 93 reactions, was used to examine the role of halogen for the ignition. The compounds containing Br formed a chain reaction with CH4 and accelerated the decomposition of CH4, while CH3Cl acted only as a fuel which was easily decomposed.