Disection of Ignition Delay Times via Laser-Schlieren Measurements of Density Gradients at Shock Fronts.
SIBLEY SCHOOL OF MECHANICAL AND AEROSPACE ENGINEERING ITHACA N Y
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An experimental and analytical investigation of the initiation regimes in the pyrolysis and oxidation of methane behind shock waves has been carried out. The Laser-Schlieren technique was used to measure density gradient profiles behind incident shock waves in various CH4Ar and CH4O2Ar mixtures in the temperature range 2000K to 2600K. Since the density gradient is proportional to the net rate of post-shock energy exchange, these experiments provide a highly resolved record of the net endoexothermic balance throughout the initiation regime. In the analytical study, it was possible to ascertain which of the limited number of reactions and rates were consistent with the observed density profiles. While the induction times agreed with previous correlations, currently proposed oxidation mechanisms do not fully reproduce the observed shapes of the density gradients.
- Physical Chemistry
- Combustion and Ignition