We performed a computational study of an important reaction in the combustion of hydrocarbons, C 6 H 6 , + O ( 3 P), using ab initio and RRKM methods. Density functional theory (B3LYP) was used to optimize geometries and obtain molecular vibrational frequencies, and complete basis set extrapolation (CBS-QB3) was used to obtain the energies for the reactants several transition states and products. The initial formation of a stabilized adduct is characterized by a barrier of 4.9 kcal mol -1 , in good agreement with the measured activation energy for this reaction. All product channels originate from rearrangement or decomposition of this adduct, which our calculations suggest is a triplet ground state. All of our ab initio calculations are thus conducted on the triplet surface. There are several products that are energetically accessible at combustion temperatures, but the formation of phenoxy radical, C

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A method has been developed in which the flow field predicted by Computational Fluid Dynamics (CFD) is automatically condensed into an Equivalent Reactor Network (ERN), composed of well stirred reactors, allowing rapid and accurate analysis of emissions. This paper presents the effectiveness of utilizing an ERN that is a direct abstraction of the computational flow field for combustion analysis. The CFD results are divided into reactors using various filters on flow-field variables to construct an ERN that represents the 3-D combustor flow field and flame structure. Detailed kinetics can then be used in ERN simulations to analyze effects of fuel composition and operating condition on emissions. The technique is applied to a commercial industrial gas turbine combustor fuel injector and compared against experimental emissions results. Sensitivity of emissions predictions to different parameters in the network extraction is also presented. Parameter variations in fuel flow rate are applied to the ERN to obtain relative impacts of fuel-air ratio on the emissions of NOx without requiring new CFD solutions. This automatic approach has been found to reduce the time required to construct and analyze flow field derived ERNs with detailed chemistry by 90%. A local calculation of Damko¨hler number, important for stability analysis, is also presented. This calculation also uses abstracted information from the CFD flow field and detailed-kinetics simulations for more accurate, cost-effective analysis.

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