Trajectory and momentum coherence breakdown of a liquid jet in high-density air cross-flow

An experimental study of a liquid jet injected normal to a high-density air cross-flow is presented. Kerosene and water were used in order to highlight the influence of liquid properties on the jet bending and atomization process. Two different nozzle sizes and two values of the air pressure were used to gain some insight on the dependence of these parameters on the jet evolution. A shadow-graphic technique has been used and an image statistical analysis procedure, allowing for a fully automated determination of the jet momentum coherence breakdown point, was set up. A simple correlation between the coordinates of this point and the ratio of the liquid-to-air momentum (q) and a Weber number was found. Experimentally measured trajectories normalized with respect to the breakdown point coordinates collapse to a unique trajectory, which is well fitted by either a power or a logarithmic curve with only one parameter. This is the base for the definition of a new empirical correlation that, in the explored experimental conditions, performs better than the ones available in the literature. This fact indicates that the operatively defined momentum coherence breakdown concept subsumes the functional dependence of jet behavior on controlling parameters, at least for the explored operating conditions.