Hollow-Cone Spray Modeling for Outwardly Opening Piezoelectric Injector

Linear instability sheet atomization (LISA) breakup model has been widely used for\udmodeling hollow-cone spray. However, the model was originally developed for inwardlyopening\udpressure-swirl injectors by assuming toroidal ligament breakups. Therefore, LISA\udmodel is not suitable for simulating outwardly opening injectors having string-like\udstructures at wide spray angles. Furthermore, the varying area and shape of the annular\udnozzle exit makes the modeling difficult. In this study, a new spray modeling was proposed\udfor outwardly opening hollow-cone injector. The injection velocities are computed from the\udgiven mas flow rate and injection pressure regardless of ambiguous nozzle exit geometries.\udThe modified Kelvin-Helmholtz and Rayleigh-Taylor (KH-RT) breakup model is used with\udadjusted initial Sauter mean diameter (SMD) for modeling breakup of string-like liquid film\udspray. Liquid spray injection was modeled using Lagrangian discrete parcel method within\udthe framework of commercial CFD software CONVERGE, and the detailed model was\udimplemented by user defined functions. It was found that the new model predicted the liquid\udpenetration length and local SMD accurately for various fuels and chamber conditions