Is Ignition In A Shock Tube Homogeneous? An Experimental Study Behind Reflected Shock Waves

In this study, new ignition delay times and high-speed images were taken behind reflected shockwaves during hydrogen/oxygen ignition to probe the homogenieity of ignition process and their effects on interpreting ignition delay times. Experimental conditions were temperatures between 941-1177K and pressures between 2.87-3.45atm for a 8%H2/4%O2/Ar mixture. Experiments were conducted in both a clean and dirty shock tube as we did recently in other hydrogen mixtures. Ignition delay times showed no significant deviations between these two types of tests, but endwall image sequences conducted in a dirty facility showed a large amount of dirt and soot particulates, clouding the images during preignition. Current high-speed results for ignition delay times confirm previous literature studies conducted using without imaging and chemical kinetic modeling