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Show Case 4 is the same stoichiometry. The stoichiometry because thermal NOx reactions. as case flue NO there is 1 except for the increased increases for the lean more available 02 for the Cases 5 and 6 are the same as case 1 except with increased amounts of oxygen enrichment in t he air stream. These cases were not completed at the time of this writing. It is expected that they will show increasing levels of NOx due to the increased flame temperatures. Figures 4 and 5 show the predicted surface contour plots for CH4 and 02 respecti vely. Both of these species are quickly expended near the burner outlet. Figures 6 and 7 show the predicted temperatures for the base case on profile and surface contour plots respecti vely. As expected, the highest temperatures are along the centerline in the vicinity of the flame. Figures 8 and 9 show the predicted NO on profile and surface contour plots respectively. It is interesting to note the · saddle point in Figure 11 which would seem to suggest that there are some reactions at that point which convert NO to some other species. Figure 10 shows a graph of flue NO as a function of burner stoichiometry for the model predictions and the experimental data measured in the lab furnace. The graph shows that the trends are the same, but the predicted val\les are about an order of magnitude higher than the measured values. Figure 11 shows a plot of flue NO as a function of percent oxygen in the oxidant. At the time of this wri ting, the model results for cases 5 and 6 were not available. Conclusions GRREK appears to predict the correct trend for flue NO as a function of burner stoichiometry, but the predicted values are about an order of magni tude higher than the measured data. According to GRREK, the furnace wall temperature and prompt NOx are not important in flue NO production for the combustion system analyzed. Future Work In order to improve the accuracy of the model, micromixing effects will be included by adding a first order closure model , involving a single parameter, to the turbulent concentration equations. The closure model chosen, derived from a mechanistic model of turbulent mixing is that developed by Tarbel110 • The micromixing parameter is the -6- |