Modeling atomization processes of pressure-swirl hollow-cone fuel sprays

A sheet spray model is proposed to study the atomization and breakup processes of hollow-cone fuel sprays resulting from pressure-swirl injectors which have potential for use in direct-injection gasoline engines. Atomization is described using a method whereby ''blobs'' that represents the liquid sheet outside the injector nozzle are injected with sizes equal to the sheet thickness. Breakup of the blobs and the subsequent drops is modeled using a modified Taylor analogy breakup (TAB) model in which the originally used chi-squared size distribution for the breakup drops is replaced by a Rosin-Rammler distribution for the hollow-cone sprays considered, since the former distribution was found to result in an overestimated population of large drops. The model is implemented in a multidimensional computer code and used to study pressure-swirl atomized sprays. Detailed comparisons of computed and experimentally determined spray characteristics such as spray structures, spray tip penetrations, drop sizes, and their distribution are made, and good levels of agreement are obtained.