Spray characteristics of aerated-liquid pressure atomizers

The atomizing performance of a novel type of injector is investigated. Essentially, the injector comprises a plain-orifice atomizer with means for injecting air or gas into the liquid upstream of the final discharge orifice. Measurements of mean drop size and drop-size distribution are made using a Malvern spray analyzer. The liquid employed is water, and all tests are carried out at normal atmospheric pressure. Water injection pressures are varied from 34.5 to 690 kPa (5 to 100 psid) and air/liquid ratios from 0.002 to 0.022 by mass. The results obtained with injector orifice diameters of 0.8,1.6, and 2.44 mm show that good atomization can be achieved using only small amounts of atomizing gas at injection pressures down to 34.5 kPa (5 psi). The system appears to have considerable potential for practical applications in which the available gas and liquid pressures are low and in which small holes and flow passages cannot be employed owing to the risk of plugging by contaminants in the liquid.