Modeling Needle Motion Influence on Nozzle Flow in High Pressure Injection System

This paper deals with the numerical investigation of a Diesel engine high pressure DI system in which the influence of needle motion characteristics on the internal injector flows is evaluated; a radial perturbation of the axial needle motion has been imposed to analyze its role over the nozzle flow features. The developed model is based on the coupling of two computational tools. With the former one, AMESim code, the injector has been modeled; the results obtained from the injector simulation, in terms of injection needle lift time evolution, have been used to initialize the latter computation tool, FIRE code, in which 3D flow numerical investigation of the internal injector flows has been performed. Details of the adopted modeling strategy are presented and the results of each simulation step are shown.