Experimental and numerical studies of high pressure multiple injection sprays
- Univ. of Wisconsin, Madison, WI (United States)
Characterization of high pressure diesel sprays has been performed both experimentally and numerically. The experimental study was conducted using a fuel injection system which has a capability of producing multiple injection sprays. The fuel sprays were injected from a multi-hole nozzle into a pressurized cylindrical chamber with optical windows. In order to investigate the effects of a multiple injection strategy on spray characteristics, a double injection spray with the mass evenly distributed between the first and second sprays, and a 1 millisecond dwell between sprays was compared with a single injection spray. Transient spray tip penetration lengths and spray angles were obtained from high speed photographic spray images. The numerical study was conducted using the KIVA-II code for the operating conditions used in the spray experiments. The KIVA code was modified to include a drag model based on droplet distortions calculated by the DDB model, a breakup model that includes the effect of Rayleigh-Taylor accelerative instabilities on the droplets and a new drop collision model. The effect of the drop drag model was found to be very important in drop size predictions. The new breakup model was found to give more reasonable predictions of the distribution of drop sizes in the spray. The revised drop collision model gave more accurate drop sizes at the end of the injections where the standard model tended to over predict drop coalescences. The KIVA calculations show reasonable agreement with the experimental results, and indicate that the present spray breakup model characterizes the physical phenomena well at pressures and injection velocities currently seen in diesel engines.
- OSTI ID:
- 277858
- Report Number(s):
- CONF-960204--; ISBN 1-56091-762-8
- Country of Publication:
- United States
- Language:
- English
Similar Records
MODELING THE INFLUENCE OF NOZZLE-GENERATED TURBULENCE ON DIESEL SPRAYS
Three-dimensional modeling of diesel engine intake flow, combustion and emissions-II