Experimental study of high temperature oxidation of dimethyl ether, n-butanol and methane

Abstract An experimental study of the kinetics of oxidation of dimethyl ether, n-butanol, and methane was carried out using emission and atomic resonance absorption spectroscopy. All experiments were performed in a shock tube behind reflected shock wave in a wide temperature range from 1890 to 3250 K at a pressure of 2.4 ± 0.4 bar. In all investigated conditions, the peaks of nonequilibrium UV radiation of electronically excited carbon monoxide CO(a3Πr) were observed. Besides, the resonant absorption profiles of atomic oxygen in the ground electronic state O(3P) converted to O-atom concentration profiles were for the first time measured at this temperature range. For simulating the CO(a3Πr) radiation experimental profiles a kinetic mechanism of its formation and consumption was developed. This mechanism was implemented into existing comprehensive detailed kinetic models (such as Ranzi et al. (2014), Vasu and Sarathy (2013), NUIG Mech 56.54 (2013), GRI-Mech 3.0 (1999) and Alviso et al. (2018)), which were then tested on the obtained experimental profiles of atomic oxygen and electronically excited carbon monoxide. It was shown that the proposed CO(a3Πr) sub-mechanism nearly correct describes the ongoing reaction processes, however, complete compliance was not achieved. To elucidate reactions responsible for the differences observed, a sensitivity analysis was performed. As a result, the most important elementary reactions were determined.