The predictive capability of an automatically generated combustion chemistry mechanism: Chemical structures of premixed iso-butanol flames

摘要

The chemical compositions of four low-pressure premixed flames of iso-butanol are investigated with an emphasis on assessing the predictive capabilities of an automatically generated combustion chemistry model. This kinetic model had been extensively tested against earlier experimental data and also shows impressive capabilities for predicting the new flame data presented here. The new set of data consists of isomer-resolved mole fraction profiles for more than 40 species in each of the four flames and provides a comprehensive benchmark for testing of any combustion chemistry model for iso-butanol. Isomer-specificity is achieved by analyzing flames, which are burner-stabilized at equivalence ratios of φ = 1.0-1.5 and at pressures between 15 and 30 Torr, with molecular-beam mass spectrometry and single-photon ionization by tunable vacuum-ultraviolet synchrotron radiation. Predictions of the C_2H_4O, C_3H_6O, and C_4H_8O enol-aldehyde-ketone isomers are improved compared to the earlier work by Hansen et al. [N. Hansen, M. R. Harper, W. H. Green, Phys. Chem. Chem. Phys. 13 (2011) 20262-20274] on similar n-butanol flames. A reaction path analysis identifies prominent fuel-consumption and oxidation sequences. Almost all of the species mole fraction data reported here are predicted within the measurement uncertainties of a factor of two to three. Some significant differences with previous published models are highlighted.