Ansys Forte includes advanced models to simulate multi-component fuel-spray dynamics and spray interactions with flowing multi-component gases. The modeled sub-processes include: nozzle flow, spray atomization, droplet breakup, droplet collision and coalescence, droplet vaporization, and wall impingement. Different sub-models are applied to represent the spray atomization and droplet breakup processes of solid-cone sprays and hollow-cone sprays, respectively. For solid-cone sprays, the initial spray conditions at a nozzle exit are determined through either a discharge coefficient or a nozzle-flow model, and the Kelvin-Helmholtz / Rayleigh-Taylor (KH/RT) model [11] is used for droplet breakup. For hollow-cone sprays, both the spray initialization and breakup processes are represented by the Linearized Instability Sheet Atomization (LISA) model [84] . Other spray sub-models are shared by both solid-cone and hollow-cone spray simulations.

The spray-atomization, droplet-breakup and droplet-collision models in Ansys Forte employ several advanced techniques that minimize the dependency of results on mesh size and time-step size. For solid-cone sprays, an unsteady gas-jet breakup model is used by default. For both solid-cone and hollow-cone models, additional options include a radius-of-influence (ROI) collision model and a collision mesh method. Reducing the mesh-size and time-step dependency enables accurate solutions with less computational time compared to conventional spray models, by allowing a coarser mesh near the nozzle and larger time steps during spray injection.

This chapter is organized to provide information on the main sub-models used by the various spray options. Solid-Cone Spray Models describes the solid-cone spray model, which is most often used for diesel-spray injection, while Hollow-Cone Spray Models describes the hollow-cone spray model. Sub-models specific to these types of sprays are included within these sections. Droplet Collision and Coalescence Model provides information regarding additional options that are available for both types of sprays. Multi-Component Droplet Vaporization Model describes the multi-component vaporization model and Wall Impingement Model the wall-impingement model.