Numerical Study on Flow Structures of a Hollow Cone Spray in Crossflow

In this paper, numerical investigation on the flow field structure of a hollow cone spray injected transversely into a confined crossflow is presented. The unsteady turbulent flow is predicted by adopting the Scale-Adaptive Simulation approach and the atomization of the spray is predicted by using the linear instability analysis and Taylor analogy breakup theory. The interactions between the hollow cone sprays (with two different spray angles of 80 degrees and 40 degrees) and the crossflow inside a rectangular duct (95 mm x 95 mm in cross-section) at ambient temperature and pressure are simulated. The results show that there exist six large-scale vortex structures in the mixing flow field, namely the Counter-rotating Vortex Pair (CVP), the horseshoe vortex, the shear layer vortex, the hairpin vortex, the wake vortex, and the upright vortex. The formation mechanisms of these vortices are analyzed. The CVP and the hairpin vortex dominate the flow field and exert significant influences on droplet dispersion in span-wise and stream-wise directions respectively. The influence of the spray angle on the vorticity of the CVP is small, but a smaller spray angle can lead to larger depths of the spray and the CVP and a smaller distance between both CVP cores.