| OCR Text |
Show arrangement, the oxidant mass flow rate was subsequently modified to maintain an oxygen concentration between 2 - 3 % (vol. wet) at the flue. The change in oxygen mass flow rate resulted in a change in oxygen velocity through the specific lance nozzle since the nozzle diameter remained constant for a given test series. For the conditions of this study, the variation in oxygen flow velocity was typically no more than 15 % when the nitrogen furnace concentration was varied from 0 to 77 % . Gas samples were extracted from the furnace flue via a water-cooled stainless steel probe and a vacuum-pump based sampling system. After the water was removed from the gas sample, the sample was sent to the same gas analysis instruments mentioned previously in the last section. In addition to those instruments, a Horiba CLA-510S NO analyzer was employed. A N02 to NO converter was not used for any of the tests, hence only NO was measured. However, the molecular weight of N02 was used for the calculation of all of the appropriate emission indices. The amount of water in the gas sample was calculated from a hydrogen atom balance. RESULTS AND DISCUSSION The results of both the bench-scale apparatus and laboratory-scale furnace experiments are delineated next. o Dolo 70 - Rlcou and Spalding 60 20 10 Fig. 5. The mass entrainment ratio, (Ills + 1Ilo)/1Ilo, plotted as a function of the nondimensional distance, (x/do)(p/po)o.s, for an air jet in an air surrounding gas at ambient temperature. The entrainment measurements compare well with the correlation (solid line) developed by Ricou and Spalding [2]. Mass Entrainment The mass entrainment ratio of both a nonreacting and reacting jet were measured for a number of cases using the bench-scale apparatus equipped with the windowless entrainment chamber using the acetylene torch method described in the experimental section. The mass entrainment measurements of an air jet (10000< Reo < 500(0) into an air environment made in this study are shown in Fig. 5. More specifically, the mass entrainment ratio, (Ills +1llo)/IDa, is plotted as function of the nondimensional distance, (x/do)(p/po)o.s, where Ills is the mass flow rate of the surrounding gas, Illo is the mass flow rate of the jet at the injector exit, Ps is the surrounding-gas density, Po is the jet density and do is the injector diameter. The distance from the injector exit to a given height along the jet axis is represented by x. In terms of the bench-scale apparatus, x represents the distance from the injector exit to the entrainment chamber exit (at the Inconel insert). For comparison purposes, the mass entrainment correlation developed by Ricou and Spalding [2] (Eq. 1) is shown in Fig. 5 as well. The 8 |
