Computational investigation of atomization

Author / Creator

Tryggvason, Grétar, author

Available as

Online

Summary

Atomization of liquid fuels is studied by numerical simulations. The Navier-Stokes equations are solved by a finite difference/front tracking technique that allows resolution of inertia! and viscou...

Atomization of liquid fuels is studied by numerical simulations. The Navier-Stokes equations are solved by a finite difference/front tracking technique that allows resolution of inertia! and viscous forces as well as the inclusion of surface tension at the deformable boundary between the fuel and the air. The secondary breakup of drops has been examined by extensive axisymmetric simulation of four systems: Impulsive and gradual disturbances for two different density ratios (1.15 and 10). At low density ratios. the density disappears as an independent control parameter and we have shown that the low density results apply to density ratios as high as two if we rescale time using the Boussinesq approximation. In addition to full simulations where the Navier-Stokes equations are solved a few inviscid simulations have also been done for the small density ratio case to isolate the effect of viscosity. The breakup of a planar interface has been examined. The presence of surface tension leads to the generation of fingers of interpenetrating fluids. In the limit of a small density ratio the evolution is symmetric, but for large density stratification the large amplitude stage consists of narrow fingers of the denser fluid penetrating into the less denser one. The dependency of the density difference is explained in terms of the advection of interfacial vorticity by the density weighted mean velocity.

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