The combustion efficiency and intermediate products of steady and oscillating flames in mesoscale ducts were studied experimentally using gas chromatography and mass spectrometry (GC/MS). Rich mixtures of methane-oxygen were burned in straight quartz ducts with one end open to the atmosphere. Even though the initial mixtures were rich, complete combustion was observed for all flame phenomenologies, since the excess fuel allows a diffusion flame to be maintained at the duct exit. Complete combustion was observed even in the case of oscillating flames, despite the apparent gaps in combustion that would seem to exist due to the periodic extinction and reignition events inherent to these flames. The products of the rich flame fronts within the tubes were also examined and found to be primarily carbon monoxide, strongly suggesting that simultaneous generation of hydrogen also occurs. This raises the possibility that these flames could provide both elevated temperatures and point-of-use generation of hydrogen for micropower systems.
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