Abstract
The induction periods of shock-heated methane-oxygen-argon-mixtures were measured over a wide range of mixture ratios. The methane decay behind the reflected shock wave was monitored using an InSb-photodiode at a wavelength of 3.43 µm. Both the measured induction periods and the observed emission profiles were compared with the values obtained from computer simulation using reaction kinetics. The results were as follows: (1) The emission intensity at 3.43 µm in-creased during the induction period in a mixture less diluted with argon, while that of a mixture highly diluted with argon remained constant. If the reaction step CH3+O2=CH2O+OH is replaced with the step CH3+O2=CH3O+O in the methane oxidation mechanism developed in the authors' laboratory, the calculated induction periods agree well with the measured ones over a wide range of mixture ratios.