Investigation of the mechanism of chemical ionization accompanying high-temperature oxidation of methane in shock waves

The ionization of methane--oxygen mixture behind reflected shock waves was studied experimentally and its kinetic parameters were determined: the rate of ionization, electron concentration, and electron yield per consumed methane molecule. The results of a numerical kinetic calculation of the electron concentration profile as a function of time, as well as the electron yield, describe satisfactorily the experimental data obtained with the help of a uhf interferometer with high spatial resolution. It was established that the rate of chemical ionization of a methane--oxygen mixture exceeds by many orders of magnitude the rate of ionization of the trace sodium impurities. This makes it possible to study it in hydrocarbon systems in the presence of unavoidable alkali contaminants under experimental conditions.