Ionization and chemiluminescence during the progressive aeration of methane flames

摘要: Abstract Saturation currents and chemiluminescence, especially at the CH ∗ C 2 wavelengths, are measured for a range of small, laminar methane flames during progressive addition air, with principal objective distinguishing between pure diffusion flames, premixed compositions falling upper lower flammability limits, broad aerated lying in these regimes. Flame areas defined by loci maximum luminosity schlieren contours were recorded, so that saturation current densities, emission per unit flame area, as well burning velocities could be deduced. For admixtures less than 70 vol.%, air appears to act, surprisingly, an inert diluent regards currents, essentially proportional fuel flow alone. Much same applies chemiluminescence. However, contours, which recorded both provide basis velocity measurements explore density changes reactants, indicated presence burner – stabilised propagating reaction zone ahead luminous surface starting around 50 vol.% possibly even admixtures. This evidence steep change refractive index is indicative involving added oxygen, however generates no chemi-ionization emits light. Even photographing radiation emitted wavelengths shows sign its existence. Its about 10 cm/s, when stabilized surrounding flame. The most plausible rationale observations formation syngas partial oxidation methane. subsequent CO H known occur without or appreciable light emission.