Investigation of the chemical structures of laminar premixed flames fueled by acetaldehyde

Abstract

Acetaldehyde is a key intermediate formed during the combustion of hydrocarbon and oxygenated fuels, and its role as an air pollution is concern-arousing. A better understanding of its combustion characteristics is of significance in developing core mechanisms and reducing the associated emissions. In this work, chemical structures of low-pressure laminar premixed acetaldehyde flames with equivalence ratios of 1.7 and 1.0 were measured by employing molecular-beam mass spectrometry with synchrotron vacuum ultraviolet light for ionization. Totally, about 40 species were identified and their mole fraction profiles are reported with well estimated uncertainty. To our knowledge, some oxygenated species, such as ethenol and butanal, were measured for the first time in acetaldehyde flames. Experimental species mole fraction profiles were compared with modeling results using several available kinetic mechanisms. These mechanisms well reproduce the mole fraction profiles of the major species and the C1/C2 hydrocarbon intermediates, however, their unsatisfactory predictive capability for some fuel-related oxygenated intermediates, such as C2H3O isomers, suggests that the acetaldehyde sub-mechanism needs further investigation. Our experimental results provide valuable information for future mechanism development.