Photoionization mass spectrometry and modeling study of a low-pressure premixed flame of ethyl pentanoate (ethyl valerate)

Abstract

In order to get insight into the decomposition and high-temperature oxidation kinetics of ethyl pentanoate in combustion processes, a stoichiometric premixed burner-stabilized flame of ethyl pentanoate/O2/Ar mixture at low pressure (20Torr) was investigated by molecular-beam mass spectrometry combined with single-photon ionization by vacuum ultraviolet radiation from the Advanced Light Source (ALS) in Berkeley, CA, USA. Mole fraction profiles of 43 species were measured in the flame and compared with those calculated using a detailed chemical kinetic mechanism proposed by Dayma et al. (2012) for ethyl pentanoate oxidation. Although mole fraction profiles of major species and several intermediates were predicted quite accurately by the model, significant discrepancies between the measured and modeled peak mole fractions of many intermediates in the flame were observed. A kinetic analysis of the main reaction pathways of ethyl pentanoate oxidation was performed to trace the origins of these discrepancies. It was concluded that the reaction pathways responsible for consumption of primary radicals formed directly from the fuel molecule as well as of the products of successive β-scission reactions should be revised when developing a next-generation combustion model for ethyl pentanoate.