OCR Text |
Show 1.3.15 at the end of the burning sprays of No. 2 oil, SRC-II oil, and their emulsions with water. This figure reveals that the maximum concentration of CO in SRC-II oil flame is roughly half that in No. 2 oil flame. The emulsification decreases CO concentration in both flames. The effects of fuel emulsification with water on the radial profiles of nitric oxide in the product gases of the spray flames of No. 2 oil and SRC-II oil are shown in Figure 5. It is interesting to note that both peak and average values of NO concentration increase slightly in No. 2 oil flames when the fuel is emulsified. Although the NO concentration dips slightly on the axis of SRC-II oil flame, neither its peak value nor its rate of decline along the radius change significantly with fuel emulsification. As expected, the NO concentration is considerably higher in SRC-II oil flame than in No. 2 oil flame. Finally, Figure 6 shows that although there is no significant difference in the peak values of S0? concentration between the flames of two oils, the emulsification increases the average SO- concentration in No. 2 oil flames and does not change it markedly in SRC-II oil flames. DISCUSSION The combustion behavior of emulsified petroleum fuels has been a subject of a number of fundamental studies [8,10,11,17,18]. These studies have been focused on the mechanism by which the water present in the oil-water emulsion droplets affects the burning rate and pollutant formation characteristics. The results of these studies, in general, suggest the following phenomena. The first one is a physical phenomenon, the so-called microexplosion of droplets, caused by the differential evaporation |