MEASUREMENTS AND MODELING OF OH AND NO IN PREMIXED C2H6 O-2/N-2 FLAMES AT ATMOSPHERIC-PRESSURE/

We present laser-induced fluorescence (LIF) measurements of OH and NO concentrations in six premixed, atmospheric-pressure, laminar, flat C2 H6/O-2/N-2 flames. The names have a similar dilution ratio and total R ow rate, while the equivalence ratios vary between 0.0 and 1.6. Using the data, we evaluate the predictions from two chemical kinetics model s. These two models are the Glarborg, Miller, and Kee mechanism as mod ified by Drake and Blint (GMK-DB) and the GRI-Mech mechanism, version 2.11. (GRI), Two temperature profiles are used to generate the predict ions from each model: a measured temperature profile and a predicted p rofile based on the energy equation. For the GMK-DB model, the measure d temperature profile tends to give better results than the calculated temperature profile for the OH concentrations. Both the NO and OH con centration profiles are well predicted by the GMK-DB model in lean fla mes, while poorer agreement is generally obtained between measurements and modeling in the rich flames. The predictions for the GRI mechanis m are satisfactory for both OH and NO in the lean flames but also beco me poorer in the richer flames. The two temperature profiles do not gi ve significantly different results when using the GRI model in lean fl ames, but in rich flames, the measured temperature profile tends to gi ve better agreement with the LIF measurements. The results indicate th at while improved temperature measurements would be beneficial, furthe r refinement of the chemical kinetics is required to improve the agree ment between the predicted NO and OH concentration profiles in the ric h flames. in particular, it is important that the rate coefficient for the reaction CH + N-2 <-> HCN + N be more firmly established.