Spectral uncertainty quantification, propagation and optimization of a detailed kinetic model for ethylene combustion

The ability of a reaction model to predict the combustion behavior of a fuel relies on the rigorous quantification of the kinetic rate parameter uncertainty. Although the accuracy of a detailed kinetic model may be ensured, in principle, by a multi-parameter optimization, the inherent uncertainties in the fundamental combustion targets used for optimization cause the resulting optimized model to be characterized by a finite kinetic parameter space. In this work, spectral expansion techniques are developed and employed to quantify these uncertainties, using an as-compiled, detailed, H2/CO/C1-C4 kinetic model for ethylene combustion as an example. Uncertainty was quantified for both the as-compiled model and the optimized model, and propagated into a wide variety of combustion experiment and conditions. Application of the spectral uncertainty method in mechanism reduction is also discussed.