Simulation of Liquid Jet Atomization for Fuel Sprays by Means of a Cascade Drop Breakup Model

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. The computations are in good agreement with the spray penetrations and show acceptable correspondence in the fuel-gas mixture formation. Applications of the model to reacting sprays have shown good agreement in ignition time and location with experimental data, where the auto-ignition has been modeled by a new approach using a single transport equation in combination with a reduced kinetic scheme.