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Show 0.4 r 0.3 0.2 0.1 A o b D dl D SLURRY FLOW ~425 Ib/hr O AIR FLOW ~150 Ib/hr COUNT RATIO OF PULVERIZED COAL IN THE SLURRY 0.4 0.8 1.2 1.6 AIR TO FUEL MASS FLOW RATIO 2.0 2.4 Figure 7 Ratio of the Number of Particles in T w o Size Ranges as a Function of Air-to-Fuel Ratio At air-to-fuel ratios above 0.4, the data shows that the relative number of large particles decreases. The decrease in large droplets is consistent with general trends in the atomization process. In liquid atomization, the relative number of large drops would eventually reach a value of 0.0 as the A/F ratio is increased. With coal-water slurries however, the relative number of the larger particles will reach a nonzero limit based on size distribution of the pulverized coal. This limiting value is also shown in Figure 7. At high A/F ratios, the relative number of particles is greater than for the pulverized coal, but appears to asymptotically approach the limiting value. The relative number ratio for A/F ratios below 0.35 does not appear consistent with the rest of the data. Yet it was at these A/F ratios that a preponderance of large droplets was observed in the combustion tests. At these test conditions then the limited range of measured drop sizes is insufficient to interpret the atomization process. -11- |