Experimental Collision and Swirl of CFD Simulated Fuel Sprays in a Dual Injector Cylinder Head Concept

Abstract

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. These effects were simulated using of CFD (Computational Fluid Dynamics) with OpenFOAM®, and qualitatively compared under non-reacting conditions with images of recorded videos of the sprays. The results show a reduced diameter of the fuel drops with the direct collision of the fuel sprays and a bigger diameter of those drops with the swirl because of a higher level of coalescence. Even when the diameter of the atomized fuel drops with a single spray is similar to the diameter of the two direct colliding sprays, the required injection time for the two injectors is 50% less. Our work aims to contribute to an enhanced fuel atomization and to the next development stage of internal combustion engines.