Characteristics of laminar premixed CH₄/CO/air opposed-jet flames

The characteristics of laminar premixed CH₄/CO/air opposed-jet flames are experimentally and numerically investigated. The premixed flames are operated at a fixed stoichiometric condition with various fuel mixtures of CH₄ and CO. The flame front positions of the opposed-jet fames are measured using direct photographs and CH^∗ chemiluminescence images. The flame structures are calculated using the OPPDIF code coupled with multicomponent transport model and GRI-Mech 3.0 chemical kinetic mechanisms, while the PREMIX code is employed to investigate the laminar burning velocity. Results show that the measured and calculated flame front positions are in excellent agreement. The calculated flame structures suggest that the premixed CH₄/CO/air flames can be categorized into CH₄-like or CO-like flames, according to the spatial distribution of CO concentration. In addition, the calculated maximum laminar burning velocity of the premixed CH₄/CO/air flames is found when the volumetric CH₄ concentration is about 10% in fuel mixtures which also results in lowest CO₂ production for the blended fuels studied.