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Show intermediate flow rate of methane was employed in the CFD computation. The measurements were obtained at the end of the full burner (933 mm away from the nozzl e, that is 790 mm away from the end of the divergent) and are presented in Table 1 together with the relevant results of the CFD calculations. Table 1. Experimental Measurements. CFD CH4 (m3 / s) 4.72 X 10-3 3.42 x 10-2 8.93 x 10-3 T (K) at end 1118 1332 T (K) 1383 1453 1230 300 mm from at end of divergent divergent NO (ppm) 0 2 0.2 N02 (ppm) 0 0 0 CO (ppm) 53 302 215 ° (%) 12 10.4 12 CO2 (%) 4.6 5.9 3.8 The NOx emissions were found to be of maximum 0.2 ppm/% CO2 and about 0.1 ppm/% CO2 i n normal runn i ng cond it ions in mode A and about 20 times more in mode C by British Gas. The only measurable NOx product in the duct was NO, N02 was much less than 1 ppm although N02 is the dominant product once the gases are diluted with air. A velocity of 10 mjs at the exit of the burner in mode A has been found to give the best running conditions of the burner . 11 3.5 Analysis of the Relative Roles of Prompt-NO, Nitrous Oxide-NO, Thennal NO x and N02 In an attempt to estimate the contributlon of the N20 route to the total NOx produced in such a lean premixed atmospheric flame, several runs using the Sandia Chemkin II incorporated in the PREMIX code have been carried out with the following inputs: (i) Initial methane mol fractions of 0.075, 0. 085 and 0.095 as in the modes A, Band C used with the CFD Jackage, |