In the recent development of the gasoline combustion engine, direct injection (DI) technology has been widely used to improve fuel economy and reduce exhaust emissions. Because of the limitation of experimental techniques, the transportation of fuel within the GDI injector nozzle hole and near-field spray is not well understood. In this study, computational fluid dynamics (CFD) modelling and direct coupling of the Euler in-nozzle flow model with the Lagrangian spray model are employed to investigate the effect of different nozzle geometrical designs on the GDI spray characteristics. Euler modelling of the inside-nozzle flow reveals that a round nozzle inlet significantly increases the mass flow rate and nozzle exit velocity. A longer internal nozzle wall length results in a decrease in mass flow rate and larger droplet distribution in the nozzle near-field. At the nozzle exit, the nozzle flow parameters obtained from the Euler-based study are implemented as initial conditions for the subsequent Lagrangian-based spray model. The direct coupled Euler–Lagrangian approach is then compared with the Kelvin-Helmholtz-aerodynamic cavitation–turbulence (KH-ACT) model and the Max Planck Institute (MPI) model. The effects of injection and ambient pressure on spray characteristics are separately investigated by experimental and numerical approaches. Three different fuels, iso-octane, DMF and ethanol, are investigated using the MPI-CAB model and experimental approaches in order to gain comprehensive insight into the effect of fuel properties on spray characteristics.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:687468 |
| Date | January 2016 |
| Creators | Tu, Powen |
| Publisher | University of Birmingham |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://etheses.bham.ac.uk//id/eprint/6687/ |
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