Paper ID ICLASS06-218 AN EXPERIMENTAL AND NUMERICAL STUDY OF FLOW PROCESSES IN PRESSURE-SWIRL GDI INJECTORS

This paper demonstrates the application of optical diagnostics and numerical analysis to the study of internal flows in real-sized GDI injector nozzles. The aim of the work was to study the effect of internal geometry and driving pressure on the internal flow field and near nozzle break up processes using a combined experimental and theoretical modeling approach. Two optical diagnostic techniques were used in the study; high-speed flow visualisation and fluorescent particle image velocimetry. The high-speed flow visualisation provided qualitative and quantitative information of in-nozzle flow structure for varying nozzle and swirler geometry and driving pressure. Fluorescent particle image velocimetry provided quantitative information of the internal flow velocity field, indicating the swirl flow velocity magnitude. The numerical approach used a DNS model to investigate the internal and external flow processes. These results aid the understanding of the actual fluid mechanics processes generated by the liquid fuel and assist the future development of GDI injectors.