Basic aspects of OH(A), CH(A), and C-2(d) chemiluminescence in the reaction zone of laminar methane-air premixed flames

Detailed spatial intensity profiles of OH(A), CH(A), and C-2(d) chemiluminescence in the reaction zone were revealed in two-dimensional laminar premixed flames (phi = 0.85-1.5) using spatially resolved emission measurements with a resolution-enhanced Cassegrain-type optical probe. A numerical simulation of one-dimensional laminar premixed flames using the PREMIX code, with GRI-Mech 3.0 incorporating with reaction and quenching kinetics for OH(A), CH(A), and C-2(d), was compared with the experimental result. The measured and simulated profiles showed reasonable agreement in shape, peak location, emission zone thickness, and peak-intensity variation in fuel-lean and stoichiometric flames. We found disagreement between the experimental and numerical results under fuel-rich conditions, which likely resulted from incomplete C-2(d) chemistry used in the present study. Stoichiometry dependence of chemiluminescence peak-intensity ratio, OH(A)/CH(A), observed experimentally was clearly supported by the simulated result. (C) 2004 The Combustion Institute. Published by Elsevier Inc. All rights reserved.