Simulation of kerosene film atomization in air-assist atomizer with prefilmer

We applied the VOF method in an approximation of 2D axisymmetric swirl flow to study the primary atomization of kerosene film in an air-assist atomizer operating in conditions that are similar to cruise ones. The simulation was carried out on meshes whose characteristic element sizes were 0.78125, 1.5625, 3.125 and 6.25 µm. The solution does not change with the refinement of a mesh, when the cell size is 1.5625 µm. The obtained results indicated the presence of Kelvin-Helmholtz instability causing waves on the surface of the fuel film. After detachment of the film from the prefilmer edge, thinning of the film near the trough leads to rupture in this place. This film atomization regime can be matched with the regime identified for the atomization in an air-assist atomizer operating under standard conditions in a combustion chamber. The peculiarity of regime realization in the studied atomizer is that some fuel ligaments, appearing after film disintegration, move in radial direction into the stagnant zone. Note that the approximation of the axisymmetric swirl flow allows simulating only primary atomization. The studied problem arose due to the lack of information about the disintegration of a fuel film in an air-assist atomizer operating under conditions similar to cruise ones.