ABSTRACT
One of the main components that make GDI such an attractive option in terms of higher efficiencies and power output is the GDI inj ector. Need for fundamental knowledge of spray formations and characteristics is vital for the development of GDI injection systems. Tokuoka et al ( 1 99 1 ) and Zhang et al ( 1 99 1 ) both showed the influence of the GDI swirl atomiser on the microscopic behaviour of fuel droplets generated at low pressure. With the advancement of laser diagnostic tools, Wigley et al ( 1 998) was able to quantify the hollow cone spray of a GDI injector. Comer et al ( 1 999) used Computational Fluid Modelling (CFD) tool to predict the external flow from the GDI injector, Similarly, experimental and modelling techniques were employed by Arcoumanis et al ( 1 999) and Gavaises et al (2002) to predict the development of the hollow cone spray and the internal flow structure within the GDI inj ector. However, limited open literature is published on the characteristics of the inlet geometry and it effects on the spray of the GDI inj ection. Schmidt ( 1 997) investigated the cavitation effects in sharp edge inlet nozzle and successfully predicted the velocity data, Allen et al (2000) investigated the change in the nozzle radii on the generation of a hollow cone spray. He also showed that the removal of cavitation in the flow field enhanced the ability to collect Particle Image Velocimetry (PIV) data.
