Structure and mixing properties of pressure-atomized sprays

Abstract

A theoretical and experimental study of the dense-spray region of pressure-atomized nonevaporating sprays is described, emphasizing flows in the wind-induced and atomization breakup regimes. Mean and fluctuating velocities at the injector exit, mean liquid volume fraction distributions, and entrainment rates were measured for large-scale (9.5 and 19.1 mm injector diameters) water jets in still air at atmospheric pressure. It was found that mixing was strongly influenced by the degree of flow development at the injector exit and the breakup regime: fully developed injector flow and atomization breakup yielded the fastest mixing rates. Predictions based on the locally homogeneous flow approximation, where relative velocities between the phases were neglected, gave encouraging predictions of dense-spray properties in the near-injector region for atomization breakup, including representation of flow development effects at the injector exit.