DYNAMIC BEHAVIOUR OF METHANE OXIDATION IN PREMIXED FLOW REACTOR

Thermokinetic temperature oscillations related to oxidation of small hydrocarbons have not been extensively studied yet, because they occur in a temperature 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 CH 3 recombination path present in the methane oxidation mechanism plays a key role in modulation of temperature oscillations.