| OCR Text |
Show during combustion tests with the three burners, No. I, II and III, shown in Fig. 7. With burner No. I, as shown in Fig. 12, a considerable amount of CO left unburned is evident at positions up to 150 mm from the the slit center (cross section X3) on both sides. However, only a small amount is left unburned at the slit center line with burners No. II and III. Further, burner No. I shows a low, flat temperature distribution, while burners No. II and III have a sharp distribution with a very distinctive peak at the slit center. This difference seems a result of the fact that burner No. I only blows gas and air as parallel streams, and burners No. II and III demonstrate better mixing effects because gas and air meet at an angle. Of these latter two, burner No. Ill seems to provide the better mixing effect, due to the longer distance between the point where gas and air meet and the point of exit into the furnace. Effects of Gas and Air Flow Rates Figs. 13 and 14 show the relations between temperature and gas flow rate and between unburned CO density and air ratio in the cross section Y2 directly below burners No. I through III (level Z4). In Fig. 13, burners No. II and III show a distinctive temperature rise as the gas flow rate increases, but burner No. I shows no such tendency. It is evident from Fig. 14 that, in burner No. Ill, the amount of unburned CO decreases as the air ratio increases; burners No. 1 and II do not show this tendency. In burner No. I in particular, the unburned CO density is high, even at high |
