Improving the Predictive Accuracy for Ketene in Diacetyl Laminar Premixed Flames: Experiment and Model Analysis

Ketene is an important species in core mechanisms for
the combustion
of hydrocarbon and oxygenated fuels, but direct experiments with ketene
are challenging to conduct due to its high reactivity. Diacetyl can
be used as a precursor of ketene, and abundant ketene is present in
premixed flames of diacetyl. However, predictions of ketene in diacetyl
flames with previous models have significant uncertainties. The study
of Sun et al. [Sun, W.; Wang, J.; Huang, C.; Hansen, N.; Yang, B.Combust. Flame, 2019, 205, 11−21, DOI: 10.1016/j.combustflame.2019.03.037] shows that the flame structure measurements should be
performed under certain conditions to improve the predictive accuracy
of ketene in diacetyl flames. In this work, the structures of three
laminar premixed flames of diacetyl under atmospheric pressure in
a range of equivalence ratios are examined with flame-sampling molecular-beam
mass spectrometry (MBMS). With the new experimental data and the data
available in literature, Bayesian analysis is performed to optimize
the kinetic model. The obtained optimized model is compared with the
original one, and the results show that the optimized model agrees
better with the experimental data than the original one. The uncertainties
of the rate coefficients of some key reactions are constrained with
these experimental data, which eventually leads to smaller modeling
uncertainties for ketene concentrations under studied conditions.