Temperature‐dependent feature sensitivity analysis for combustion modeling

Abstract

Sensitivity analysis is one of the most widely used tools in kinetic modeling.Typically, it is performed by perturbing the A-factors of the individual reaction rate coefficients and monitoring the effect of these perturbations on the observables of interest. However, the sensitivity coefficients obtained in this manner do not contain any information on possible temperature dependent effects. Yet, in many combustion processes, especially in premixed flames, the system undergoes substantial temperature changes, and the relative importance of individual reaction rates may vary significantly within the flame. An extension of conventional sensitivity analysis developed in the present work provides the means of identifying the temperatures at which individual reaction rate coefficients are most important as a function of input parameters and specific experimental conditions. The obtained information is demonstrated to be of critical relevance in optimizing complex reaction schemes against multiple experimental targets.Applications of the presented approach are not limited to sensitivities with respect to reaction rate coefficients; the method can be used for any temperaturedependent property of interest (such as binary diffusion coefficients). This application is also demonstrated in this paper.

Uncertainty propagation of chemical kinetics parameters and binary diffusion coefficients in predicting extinction limits of hydrogen/oxygen/nitrogen non-premixed flames

“…In the modified approach of Middha et al [28], selected binary diffusion coefficients and corresponding multi-component collision integrals are fitted based on high-level quantum chemistry numerical computations of the molecular potential functions. Some investigators have found that the effect of the modified transport approach is relatively small and within the experimental uncertainty of laminar flame propagation velocity measurement [9,28], whereas Dong et al [10] have pointed out that the counterflow configuration may be more heavily affected. As shown in Figures 1 and 2, the effect of the transport database can be as large as the experimental uncertainty of the extinction strain rate.…”

“…This assertion is usually a consequence of the assessment of the relative importance between chemical and transport parameters. The importance of binary diffusion coefficients in premixed laminar flames has been studied in the past by different groups [7][8][9][10]. By employing different methods of local sensitivity analysis, they showed that, under certain conditions, transport coefficients can significantly influence flame properties.…”

A comprehensive kinetic mechanism for CO, CH2O, and CH3OH combustion

“…Recently, Zhao et al [43] introduced a methodology to determine the temperature-dependent sensitivity of premixed laminar flame speeds to elementary rate constant and transport properties. Analyses were conducted by locally perturbing the parameter with a Gaussian function profile.…”

Transforming data into knowledge—Process Informatics for combustion chemistry

“…Recent developments place further emphasis on global aspects [40][41][42][43][44] and extend sensitivity analysis to transport properties [45,46] and uncertainties [47][48][49][50].…”