Parameters analysis of injector internal flow for gasoline direct injection engine

In order to study the internal flow characteristics of injector and the influence parameters of holes orifice flow for gasoline direct injection engine, the Euler multifluid model was established and verified by experiments. Based on the relevant parameters analysis with different mediums and different pressure difference between inlet and outlet section, the influence parameters of holes outlet section were investigated. The results show that the cavitation level increases with the increasing of bubble number density, while the cavitation flow in nozzle becomes constant when the bubble number density is over a certain value. With the increase of cavitation degree, the average velocity increases with decreased average turbulence energy at the nozzle outlet section. The cavitation can be intensified by the enhancing of pressure difference between inlet and outlet of injector. The pressure oscillation from flow disturbances and relative motion between flow mediums are beneficial to cavitation. For high pressure difference between nozzle inlet and outlet section, the turbulence energy affected by pressure oscillation is not ignorable. The discharge coefficient of nozzle is mainly influenced by the cavitation degree.