Low Temperature Ignition Properties of N-Butanol: Key Uncertainties and Constraints
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Date
2015
Journal Title
Journal ISSN
Volume Title
Publisher
Laboratory of Heterogeneous Mixtures and Combustion Systems
Abstract
A recent kinetic mechanism (Sarathy et al., 2012) describing the low temperature oxidation of n-butanol was
investigated using both local and global sensitivity/uncertainty analysis methods with ignition delays as
predictive targets over temperature ranges of 678-898 K and equivalence ratios ranging from 0.5-2.0 at 15 bar.
The study incorporates the effects of uncertainties in forward rate constants on the predicted outputs, providing
information on the robustness of the mechanism over a range of operating conditions. A global sampling
technique was employed for the determination of predictive error bars, and a high dimensional model
representation (HDMR) method was further utilised for the calculation of global sensitivity indices following the
application of a linear screening method. Predicted ignition delay distributions spanning up to an order of
magnitude indicate the need for better quantification of the most dominant reaction rate parameters. The
calculated first-order sensitivities from the HDMR study show the main fuel hydrogen abstraction pathways via
OH as the major contributors to the predicted uncertainties. Sensitivities indicate that no individual rate constant
dominates uncertainties under any of the conditions studied, but that strong constraints on the branching ratio for
H abstraction by OH at the α and γ sites are provided by the measurements.
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Citation
Agbro, E., Materego, M., Lawes, M. and Tomlin, A.S., 2015. Low temperature ignition properties of n-butanol: key uncertainties and constraints. HMCS.