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Cavitation is the major cause of the effective flow area reduction in fuel nozzles, together with mechanical damage, which leads to an increase of pressure losses. This paper describes the effect of different geometries along the fuel nozzle holes simulated with OpenFOAM® to control the cavitation and shape of the fuel jet. Previous work has only focused on the development trend towards conical spray holes that tapers towards the outlet with a strong rounded inlet edge, to increase the static pressure and thus reduce the cavitation tendency in nozzles; however, the jet forms a very narrow cone angle. The aim of this study is to evaluate the effect of constricted, expanded and gradually wider nozzles holes. The simulation reveals that the cavitation level can be changed and controlled depending on the geometry of the nozzle holes, the wider the inlet, the less is the cavitation; at the same time, the narrower the outlet, the better is the fuel atomization.

A higher level of atomization of the fuel leads to a more homogeneous mixture with the air in internal combustion engines, whether they are equipped with direct injection or port fuel injected systems. The further break-up of the atomized fuel drops by the interaction of two fuel sprays is described in this paper. In the present research, a simulation of the collision and swirl of two fuel sprays in a double-injector engine concept is carried out through a qualitative comparison with the images obtained from the recorded video of the sprays and the results of the simulation. Previous work simulated and tested the spray interaction of fuel injectors on the top of the combustion chamber; while this research proposes a new approach to reduce the diameter of the atomized fuel drops through the direct collision of the sprays with injectors located oppositely and fully horizontally to get advantage of the flow’s momentum.