NO Formation Routes Research Articles

PDF MODELING OF CO AND NO FORMATION IN LEAN PREMIXED METHANE FLAMES

In this paper, CO and NO formation in a premixed turbulent methane flame is simulated with a stochastic model of combustion. The model proposed is a combination of both the computational fluid dynamics and the Monte Carlo methods for the solution of the joint probability density function. Finite chemical kinetics is represented by a GRI-derived reduced-chemistry model. This resultant model is used to simulate a lean, premixed, bluff-body, stabilized flame for which experimental data are available. Under this condition, the prediction of NO formation is a challenge because of its low concentrations (typically a few parts per million) and because every NO-formation route is relevant. The model used for the molecular mixing includes a variable mixing time, covering the range from the Kolmogorov scale to the integral scale. A lookup table is used to estimate the thermochemical properties and is found to be more adequate than direct integration. The results are compared with an experimental database.

Stochastic Simulation of NO Formation in Lean Premixed Methane Flames

A stochastic model of combustion and NOX formation in premixed turbulent methane flames is described. The model is based on the combination of Computational Fluid Dynamics and Monic Carlo methods for the solution of the joint scalar Probability Density Function. Finite chemical rates are represented with several alternative reduced-chemistry systems, of both the global and systematically-reduced types. The model is applied to the investigation of a lean, premixed, bluff-body-stabilized flame, for which experimental data exist. In these conditions, the prediction of NO formation is very challenging, both because of the very low values (typically a few parts per million), and because all NO formation-routes are relevant. The results obtained show good accuracy for velocities, main species and temperature, and arc very encouraging in respect of minor species, including NO.