Applications of sensitivity analysis to combustion chemistry

Combustion chemical models usually contain several hundred or thousand kinetic rate parameters. Most simulation packages calculate local concentration sensitivities, but it is frequently not easy to extract meaningful information from large sensitivity matrices. Principal component analysis is a simple post-processing technique that summarizes sensitivity information and also reveals the effect of simultaneously changing parameters. A new program package, called KINALC, has been created for the analysis of gas-phase reaction systems. This program is an extension to CHEMKIN based simulation programs. KINALC processes the concentration sensitivity information in four different ways and allows a comparison of the sensitivity information to other methods, based on the study of reaction rates and stoichiometry, for the analysis of complex mechanisms. KINALC is available through the World Wide Web. The various methods are illustrated by the analysis of a detailed chemical model for hydrogen combustion. Local sensitivity analysis of models of homogeneous hydrogen explosion and of premixed laminar hydrogen-air flame has been carried out and the sensitivity results reveal that the chemical processes are very similar in these physically different systems at the corresponding temperatures. (C) 1997 Elsevier Science Limited.