Abstract
A computational study was performed to investigate the influence of transient needle motion on gasoline direct injection (GDI) internal nozzle
ow and near-eld sprays. Simulations were conducted with a compressible
Eulerian flow solver modeling liquid, vapor, and non-condensable gas phases with a diuse interface. Variable rate generation and condensation of fuel vapor were captured using the homogeneous relaxation model (HRM). The non-flashing (spray G) and flashing (spray G2) conditions specied by the Engine Combustion Network were modeled using the nominal spray G nozzle geometry and transient needle lift and wobble were based upon ensemble averaged x-ray imaging preformed at Argonne National Lab. The minimum needle lift simulated was 5 m and dynamic mesh motion was achieved with Laplacian smoothing.
The results were qualitatively validated against experimental imaging and the experimental rate of injection profile was captured accurately using pressure boundary conditions and needle motion to actuate the injection. Needle wobble was found to have no measurable eect on the flow. Low needle lift is shown to
result in vapor generation as fuel rushes past the needle. And finally, the internal injector flow is shown tocontain many transient and interacting vortices which cause perturbations in the spray angle, fluctuations in the mass flux, and frequently result in string flash-boiling.
ow and near-eld sprays. Simulations were conducted with a compressible
Eulerian flow solver modeling liquid, vapor, and non-condensable gas phases with a diuse interface. Variable rate generation and condensation of fuel vapor were captured using the homogeneous relaxation model (HRM). The non-flashing (spray G) and flashing (spray G2) conditions specied by the Engine Combustion Network were modeled using the nominal spray G nozzle geometry and transient needle lift and wobble were based upon ensemble averaged x-ray imaging preformed at Argonne National Lab. The minimum needle lift simulated was 5 m and dynamic mesh motion was achieved with Laplacian smoothing.
The results were qualitatively validated against experimental imaging and the experimental rate of injection profile was captured accurately using pressure boundary conditions and needle motion to actuate the injection. Needle wobble was found to have no measurable eect on the flow. Low needle lift is shown to
result in vapor generation as fuel rushes past the needle. And finally, the internal injector flow is shown tocontain many transient and interacting vortices which cause perturbations in the spray angle, fluctuations in the mass flux, and frequently result in string flash-boiling.
| Original language | English |
|---|---|
| Title of host publication | ILASS-Americas 2016, 28th Annual Conference on Liquid Atomization and Spray Systems |
| Place of Publication | Irvine California USA |
| Publisher | Institute for Liquid Atomization and Spray Systems |
| Pages | 1-15 |
| Number of pages | 15 |
| Publication status | Published - 2016 |
| Externally published | Yes |
| Event | International Conference on Liquid Atomization and Spray Systems 2016: ILASS-Americas - The Henry Hotel, Dearborn , United States of America Duration: 15 May 2016 → 18 May 2016 |
Conference
| Conference | International Conference on Liquid Atomization and Spray Systems 2016 |
|---|---|
| Country/Territory | United States of America |
| City | Dearborn |
| Period | 15/05/16 → 18/05/16 |