| OCR Text |
Show 1.3.16 of oil and water that results in secondary atomization and increased turbulence which lead to enhancement of oxidation reactions and the burning rate. The microexplosion phenomenon, however, is shown to be dependent on several factors such as, volatility of oil, water droplet size, the presence of convective flow, and the ambient pressure. It is shown to be weak and not predominant under the conditions in which the droplets in a spray are subjected to in general. The second phenomenon is a thermochemical one in which the water in the emulsion limits the heating of droplets and accelerates the oxidation of soot precursor species. These phenomena can lead to the reduction in the pyrolysis rate of fuel both in the liquid and vapor phases and thus reduce the formation of particulates. A limited number of studies on the flame structure of emulsion sprays [7,9], all dealing with petroleum oil-water emulsions, is available in the literature. The findings of the spray studies generally substantiate the results of droplet studies. The carbon-hydrogen ratio of SRC-II oil is hiqher than that of No. 2 oil flame [4,5]. Consequent!v, under similar operatinq conditions, the rates of heat loss in the form of continuous radiation, particularly in the far-nozzle region of SRC-II oil flames are higher than those in corresponding No. 2 oil flames [5]. This difference in heat loss rate and the slower heat release rate caused by the larger amount of soot which burns slower relative to gaseous species, results in a lower temperature level of combustion products in SRC-II oil flame. Also, fuel pyrolysis and soot formation occur in the central core of the spray in the near-nozzle region. The drops that do not evaporate completely in the initial parts of the flame burn in the far-nozzle |
