In many combustion systems, fuel atomization and the spray breakup process play an important role in determining combustion characteristics and emission formation. Due to the ever-rising need for better fuel efficiency and lower emissions, the development of a fundamental understanding of its process is essential and remains a challenging task. The Spray-A case of the Engine Combustion Network (ECN) is considered in the study, in which liquid n-Dodecane (Spray-A) is injected at 1500 bar through a nozzle diameter of 90 μm into a constant volume vessel with an ambient density of 22.8 kg / m3 and an ambient temperature of 900 K. The unsteady Reynolds averaged Navier-Stokes (URANS) in conjunction with k-ε turbulence model is used to investigate the flow physics in a two-dimensional axisymmetric computational domain. A reduced chemical mechanism from Wang et al. [1] with 100 species and 432 reactions is invoked to represent the kinetics. The gas and liquid phases are modeled using Eulerian-Lagrangian coupled approach. The present model is validated with the experimental data as well as computational data of Pei et al. [2]. Initially, the effects of various turbulence models with modified constants are examined without introducing the breakup phenomena in the computational physics. Later on, primary and secondary breakup processes of the liquid fuel are taken into account. In the present study, we examine the effects of secondary breakup modeling on the spray under high-pressure conditions using different breakup models, including Wave, Kelvin-Helmholtz and Rayleigh-Taylor (KH-RT) and Stochastic Secondary Droplet (SSD) models. It has been observed that KH-RT model is more dominant in such high-pressure sprays and predict physics more accurately as compared to other models. The dominance of convection as well as diffusion controlled vaporization model is also realized over the diffusion controlled vaporization model. The investigations at different fuel injection pressures are also modeled and validated with the experimental data [3]. The results strongly suggest that applying high-pressure, leads to high injection velocity and momentum which enhances the air entrainment near the injector region and the mixing process.

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