Analysis of spray induced flow of gasoline direct injection (GDI) nozzle by means of time-resolved Fluorescence-Particle Image Velocimetry

The development of modern gasoline direct injection (GDI) nozzles demands profound knowledge about the mechanisms of spray transport in order to minimize emissions and maximize fuel efficiency. To receive a fundamental understanding about spray transport, the present study investigates spray induced flow of a two-hole research nozzle. Air entrainment, spray-air interaction and jet-to-jet interaction are analyzed by means of timeresolved Fluorescence-Particle Image Velocimetry (FPIV). In order to achieve phase discrimination, optical filtering is applied by doping the gaseous phase with fluorescent seeding particles. The investigation considers near field and global spray characteristics by using different field of views and optical magnifications. Flow features such as displacement and entrainment are identified and localized, providing a description of strength, growth and propagation. The exchange of momentum between spray and gas indicates jet-to-jet interaction by attraction of separate spray plumes. The investigation demonstrates a dependency between spray hole inclination angle and entrainment flow. Spray plumes with smaller inclination angels tend to be more attracted than spray plumes with higher inclination angels. ... mehrA disparity of momentum exchange is observed.