engleski

A CFD Simulation of Turbulent Piloted Diffusion Flame with Modelling of Nitrogen Oxides Formation

This paper presents a numerical simulation of a turbulent piloted methane/air jet diffusion flame using computational fluid dynamics (CFD) software FIRETM. A joint solution of detailed CFD equations for turbulent flow, combined with nitrogen oxide (NO) reaction mechanisms was used for prediction of nitrogen oxides formation. The NO formation was predicted in a post-processing mode using converged solution of a pre-calculated flame structure. The formation of NO was attributed to two chemical kinetic processes: thermal NO mechanism formed by oxidation of atmospheric nitrogen in the high-temperature post-flame region of combustion system and prompt NO mechanism formed by chemical reactions between hydrocarbon fragments and atmospheric nitrogen in fuel-rich regions of the flames. The influences of turbulent fluctuations on the nitrogen pollutant reaction process were accounted for by integrating the instantaneous values of kinetic rates with respect to fluctuating temperature over presumed PDF. The predicted NO mass fractions are compared to results obtained by a Steady Laminar Flamelet Model (SLFM) and to experimental data.

CFD; Turbulent Piloted Diffusion Flame; Nitrogen Oxides

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