Three-dimensional modeling of diesel engine intake flow, combustion and emissions
- Wisconsin Univ., Madison, WI (United States). Engine Research Center
A three-dimensional computer code (KIVA) is being modified to include state-of-the-art submodels for diesel engine flow and combustion: spray atomization, drop breakup/coalescence, multi-component fuel vaporization, spray/well interaction, ignition and combustion, wall heat transfer, unburned HC and NOx formation, soot and radiation and the intake flow process. Improved and/or new submodels which have been completed are: wall heat transfer with unsteadiness and compressibility, laminar-turbulent characteristic time combustion with unburned HC and Zeldo`vich NOx, and spray/wall impingement with rebounding and sliding drops. Results to date show that adding the effects of unsteadiness and compressibility improves the accuracy of heat transfer predictions; spray drop rebound can occur from walls at low impingement velocities (e.g., in cold-starting); larger spray drops are formed at the nozzle due to the influence of vaporization on the atomization process; a laminar-and-turbulent characteristic time combustion model has the flexibility to match measured engine combustion data over a wide range of operating conditions; and, finally the characteristic time combustion model can also be extended to allow predictions of ignition. The accuracy of the predictions is being assessed by comparisons with available measurements. Additional supporting experiments are also described briefly. To data, comparisons have been made with measured engine cylinder pressure and heat flux data for homogeneous charge, spark-ignited and compression-ignited engines, and also limited comparisons for diesel engines. The model results are in good agreement with the experiments.
- Research Organization:
- National Aeronautics and Space Administration, Cleveland, OH (United States). Lewis Research Center; Wisconsin Univ., Madison, WI (United States). Engine Research Center
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AI01-91CE50306
- OSTI ID:
- 10135213
- Report Number(s):
- DOE/NASA-1087-1; NASA/CR-189126; ON: DE92011889
- Resource Relation:
- Other Information: PBD: Mar 1992
- Country of Publication:
- United States
- Language:
- English
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