Flame inhibition activity of dmmp in opposed CH 4 /N 2 -air diffusion flames

Some phosphorus-containing compounds (PCCs), such as dimethyl methyl phosphonate (DMMP) and trimethyl phosphate, have previously been considered as potential flame inhibitors. To investigate the flame inhibition behavior of PCCs, we employ the laser-induced fluorescence (LIF) technique to quantitatively measure hydroxyl (OH) concentrations in CH 4 /N 2 -air opposed diffusion flames, undoped and doped with 0.01% or 0.1% DMMP in either the oxidizer or fuel stream, respectively. The methane content in the fuel stream ranges from 25% to 40% by volume, and the global strain rate (SR) is set at 20 s −1 . The percent reduction in total integrated OH number density in DMMP-doped flames decreases with increasing methane content, as a result of higher flame temperatures. Experimental OH profiles for DMMP-doped flames are compared with predicted profiles from kinetic modeling. The predicted reduction in total integrated OH severely underpredicts the measured reduction, thus suggesting a need for further improvements in our understanding of the chemical kinetics controlling PCC inhibition.