Dynamic behaviour of methane oxidation in premixed flow reactor

Thermokinetic temperature oscillations related to oxidation of small hydro- carbons have not been extensively studied yet, because they occur in a tem- perature and pressure range not relevant for practical applications. Exploitation of new combustion methodologies such as Mild Combustion also indicated such a phenomenology in small-hydrocarbons oxidation. In this paper, experimental characterization of dynamic behavior occurring in methane mild combustion in premixed flow conditions reported in a previous work was extended and a comparative analysis with data obtained by means of numerical studies was performed. The experimental study was carried out in an atmospheric jet-stirred flow reactor at different inlet temperature and mixture compositions. Several typologies of temperature oscillations were identified whose amplitudes and frequencies strongly depend on the temperature and carbon=oxygen ratio considered. These dynamic behaviors were tentatively explained by means of a rate of production analysis performed by using different methane oxidation kinetic models available in the literature. It was shown that the CH3 recombination path present in the methane oxidation mechanism plays a key role in modulation of temperature oscillations.