Identification of species from visible and near-infrared spectral emission of a nitromethane-air diffusion flame

Abstract

The combustion processes of nitromethane, an explosive used in many combustion applications, are not fully captured in current state-of-the-art nitromethane kinetic schemes. There is a need for data on transient species to further improve understanding of nitromethane chemistry and dynamics. This work aims to identify transient species present during nitromethane-air combustion through characterization of the spectral emission of a flame stabilized on an aluminum oxide wick at atmospheric pressure. Assignments were made using a spectral library assembled from prior literature and through comparison with spectra taken in two additional air-diffusion flames, CD3NO2 and CH3OH. Several new emitters were detected in excited electronic states: HNO*(A′), CN* (A2Σ), NO2*, and in ground electronic states: CH, OH, NH, and H2O. The previously observed reaction species CH*(A2Δ) was also observed, while formaldehyde and the characteristic C2*(A3Πg) Swan bands were not.