Influence of Internal Cavitating Flow of the Nozzle on Spray Characteristics in a Diesel Engine

Fuel atomization and penetration are known to significantly affect the combustion and emission processes in diesel engines. In the fuel supply system of diesel engines, the internal cavitaing flow of the nozzle is one of the most important effects on fuel spray characteristics. So it is necessary to simulate fuel spray coupling with internal cavitaing flow of the nozzle. In order to analyze the influence of cavitaing flow in the nozzle hole on spray, a coupling spray simulation was carried out with the output data of cavitaing flow in nozzles using FIRE v2010. The results of this work show that the characteristics of cavitating flow in orifice have an effect on both macroscopic properties, such as spray tip penetration and spray symmetry, and microscopic properties, like Sauter Mean Diameter-SMD. Moreover, the spray characteristics from three different types of nozzle were simulated to study the effect of nozzle structure on internal cavitating flow and subsequent spray, which supplies the theoretical foundation for the optimization design of the injector.