The performance characteristics of solid-cone-spray pressure-swirl atomizers

Pressure-swirl atomizers producing solid-cone sprays are commonly used in industry for cooling and cleaning applications, but there is very little published information on their atomization performance. In this experimental study, four generically representative atomizers are investigated for water supply pressures up to 2.1 MPa, for exit orifice diameters between 0.61 and 1.70 mm, and for an initial spray angle 56 +/- 8 degrees. Measurements are made of the drop sizes and velocities and of the liquid mass flux in the sprays up to 0.44 m downstream. Comparisons are made with other published data and the roles of swirl and turbulence inside the atomizers are discussed with respect to the atomization process and the structures of the sprays. In general, drop size is larger at the edges of the sprays and this effect is more marked for the more finely atomized sprays produced using the smaller atomizers. Correlations are developed for mean drop size, mean drop velocity, and drop mass flux, for the central spray region, as functions of distance downstream, atomizer size, and operating pressure. As in previous work with pressure-atomized sprays, the Weber number is of primary importance in determining drop size; however, the orifice diameter is also an important parameter. The correlations may be used when choosing atomizer sizes and operating conditions, particularly for spray cooling applications.