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A jet and droplet breakup model for high pressure-driven liquid fuel is described and validated for vaporizing sprays, and its performance is evaluated in combination with a recently developed auto-ignition model for reacting sprays under application of a KIVA-3 based code. The breakup model, presented in a previous study for non-evaporating sprays, imitates a cascade of drop breakups whereby the actual disintegration processes reflect the experimentally observed stripping or bag breakup mechanisms. The breakup condition itself is determined by the Taylor drop oscillator dynamics and the droplet injection is governed by a drop size distribution to account for the surface stripping near the nozzle exit. The formation of a fragmented liquid core is the consequence of a drop breakup delay achieved with an appropriate initial drop deformation together with the drop breakup cascade. The model has been validated for vaporizing, non-reacting sprays with experimental data.

In this investigation computational methods for the atomization process of a liquid fuel jet and the secondary breakup of droplets have been developed and tested for non-evaporating, solid-cone diesel fuel sprays injected into a cylindrical constant-volume cell using a KIVA-3 based code. The breakup of the liquid fuel is computed based on the Taylor analogy breakup model. In this new approach the droplet breakup process has been improved to account for the different breakup regimes which occur in diesel engine environments. In addition, an appropriate choice of the initial drop deformation parameters allows the simulation of a fragmented liquid core at the nozzle exit. The model enhancements have been tested by comparisons with data from phase doppler anemometry. Specifically, the droplet radius and velocity distributions have been compared over two cross-sections in the near-field region of the spray.