On the rupture of a round liquid jet: the primary atomization process

The present study analyzes the process of fragmentation of a liquid volume into a cloud of droplets, a well-known phenomenon usually denoted as primary atomization. The experimental work was performed in a single-orifice pressure-swirl atomizer. For the first time, a transition was observed in the droplet size distribution function (DSDF) that transforms from a Nukiyama–Tanasawa type to a power law dependence described by the function d − x . A non-dimensional group including atomizing pressure was identified as the controlling parameter in the transition, as in other similar fracture processes, for example in solid materials. The value obtained for the critical exponent of a power law function that best fitted the DSDF for the maximum atomizing pressure is a quantitative evidence of the three-dimensional characteristics of this process.