End Wall Imaging Of Co2 Diluted Ch4/O2/Ar Ignition Inside A Shock Tube

Experiments were performed behind reflected shockwaves to understand the effect of bifurcation of the reflected shockwave on the combustion of carbon dioxide diluted methane ignition. High-speed camera imaging taken of the end wall cross-section was compared with laser absorption and chemiluminescence emission measurements. Experiments were performed at pressures between 0.6 and 1.1 atm and temperatures between 1650 and 2050 K. The equivalence ratio for all experiments were unity and CO2 mole fraction ranged from 0.00 to 0.895. The high-speed camera images were compared to ignition delay times and methane time histories in order to understand reaction sequences occurring during the combustion process. The imaging showed that with the addition of CO2, there is much greater variance in the flame characteristics, the location of peak emissions, and the flame is only in the center of the shock tube (not covering the entire cross-section). However, the global measurement such as, ignition delay time was still able to be determined in the experiment. In addition to revealing the dynamic features of shock tube ignition, current efforts provide guidance to combustion kinetic modelers while comparing with predictions