Concerning shock-tube ignition delay times: An experimental investigation of impurities in the H2/O2 system and beyond

Shock-tube ignition delay time data have recently been called into question on the basis of possible hydrocarbon impurities that may serve to artificially accelerate ignition delay times. To assess potential sources of impurities, systematic tests were performed in highly dilute H2/O2/Ar and CH4/O2/Ar mixtures using H2O laser absorption at 1.388 µm and OH* emission at 307 nm near 1 atm and between 1257 and 2108 K. Factors investigated included...