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A computational model is proposed and analysis is carried out to study the atomization processes of hollow-cone fuel sprays from pressure-swirl injectors for a Gasoline Direct-Injection (GDI) Spark Ignition (SI) engine. The flow field inside a swirl injector is numerically analyzed, and characteristics of the liquid sheet at the nozzle exit are predicted. The intact length (i.e., breakup length) of the sheet is calculated from a semi-empirical correlation and a Sauter Mean Diameter (SMD) at the breakup location is estimated based on the classical wave instability theory. The spray dynamics that address the interactions between liquid drops and surrounding gas phase are simulated using FIRE code with modified spray models. The objective is to understand the effects of nozzle geometry and engine operating conditions on spray characteristics so that the spray structure can be optimized through the injector design to meet the fundamental requirements of GDI engines.