This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Progress in Diesel Engine Intake Flow and Combustion Modeling
Annotation ability available
Sector:
Language:
English
Abstract
The three-dimensional computer code, KIVA, is being modified to include state-of-the-art submodels for diesel engine flow and combustion. Improved and/or new submodels which have already been implemented 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. Progress on the implementation of improved spray drop drag and drop breakup models, the formulation and testing of a multistep kinetics ignition model and preliminary soot modeling results are described. In addition, the use of a block structured version of KIVA to model the intake flow process is described. A grid generation scheme has been developed for modeling realistic (complex) engine geometries, and initial computations have been made of intake flow in the manifold and combustion chamber of a two-intake-valve engine. The research also involves the use of the code to assess the effects of subprocesses on diesel engine performance. The accuracy of the predictions is being tested by comparisons with engine experiments. To date, comparisons have been made with measured engine cylinder pressure, temperature and heat flux data, and the model results are in good agreement with the experiments. Work is in progress that will allow validation of in-cylinder flow and soot formation predictions. An engine test facility is described that is being constructed to provide the needed validation data.
The diesel engine is the leading heavy-duty power plant because of its superior energy efficiency. However, because of environmental concerns, proposed federal emission standards require reductions in both nitric oxides (NOx) and particulates. A detailed understanding of combustion is required in order to work effectively at reducing these by-products of combustion within the engine cylinder, while still not compromising engine fuel economy.
The objective of this research program is to develop an analytic design tool for use by the industry to predict engine performance and emissions. It is expected that the use of advanced modeling tools will enable engine development times and costs to be reduced. The three-dimensional computer code, KIVA [1,2] is being used since it is the most developed of available codes. Part of the research involves implementing state-of-the-art submodels into KIVA for spray atomization, drop breakup/coalescence, multi-component fuel vaporization, spray/wall interaction, ignition and combustion, wall heat transfer, unburned HC and NOx formation, soot and radiation, and modeling the intake flow process.
Previous progress has been described by Reitz et al. [3,4] where it was shown: that adding the effects of unsteadiness and compressibility to the heat transfer submodel improves the accuracy of heat transfer predictions; that drop rebound should be included in spray/wall interaction models since rebound can occur from walls particularly at low impingement velocities (e.g., in cold-starting); that the influence of vaporization on the atomization process should be considered since larger spray drops are formed at the nozzle with vaporization; that 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, that the characteristic time combustion model can also be extended to allow predictions of ignition.
The implementation of improved models for the prediction of spray drop drag and breakup, and for modeling ignition and combustion, intake flow and soot formation is described in this paper.
The research also involves the use of the computer code to assess the effects of subprocesses on diesel engine performance, and the accuracy of the predictions is being tested by comparisons with engine experiments. To date, comparisons have been made with measured engine cylinder pressure, temperature and heat flux data, an the model results are in good agreement with the experiments [3, 4].
Work is also in progress that will allow validation of in-cylinder flow and soot formation predictions. An engine test facility is described that is being constructed to provide the validation data that is required in order to work effectively at improving performance and reducing emissions while not compromising the engine's fuel economy.
Authors
- Rolf D. Reitz - University of Wisconsin-Madison
- R. Giangregorio - University of Wisconsin-Madison
- G. Hampson - University of Wisconsin-Madison
- R. Hessel - University of Wisconsin-Madison
- S. Kong - University of Wisconsin-Madison
- A. Liu - University of Wisconsin-Madison
- D. Mather - University of Wisconsin-Madison
- D. Nehmer - University of Wisconsin-Madison
- M. Patterson - University of Wisconsin-Madison
- C. Pieper - University of Wisconsin-Madison
- T. Tow - University of Wisconsin-Madison
- Y. Zhu - University of Wisconsin-Madison
- C. J. Rutland - University of Wisconsin-Madison
Topic
Citation
Reitz, R., Giangregorio, R., Hampson, G., Hessel, R. et al., "Progress in Diesel Engine Intake Flow and Combustion Modeling," SAE Technical Paper 932458, 1993, https://doi.org/10.4271/932458.Also In
References
- Amsden, A.A. O'Rourke, P.J. Butler, T.D. “KIVA-II - A Computer Program for Chemically Reactive Flows with Sprays,” Los Alamos National Labs. 1989
- Amsden, A.A. O'Rourke, P.J. Butler, T.D. Meintjes, K. Fansler, T.D. “Comparisons of Computed and Measured Three-Dimensional Velocity Fields in a Motored Two-Stroke Engine,” SAE Paper 920418 1992
- Reitz, R.D. Rutland, C.J. “3-D Modeling of Diesel Engine Intake Flow Combustion and Emissions,” SAE Paper 911789 , SAE Transactions 1991
- Reitz, R.D. Ayoub, N. Gonzalez, M. Hessel, R. Kong, S. Lian, J. Pieper, C. Rutland, C.J. “Improvements in 3-D Modeling of Diesel Engine Intake Flow and Combustion,” SAE Paper 920463 1992
- Reitz, R. D. “Prospects and Challenges for Fuel Spray Research in the Automotive Industry,” Atomization and Sprays 2000, NSF Work Proceedings 89 95 Chigier N. Gaithersburg, MD July 19 1991
- Giangregorio, R.P. Zhu, Y. Reitz, R.D. “Application of Schlieren Optical Techniques for the Measurement of Gas Temperature and Turbulent Diffusivity in a Diesel Engine,” SAE Paper 1993
- Nehmer, D. University of Wisconsin-Madison 1993
- Gonzalez D. Lian, Z. W. Reitz, R.D. “Modeling Diesel Engine Spray Vaporization and Combustion,” SAE Paper 920579 1992
- Liu, A.B. Mather, D. Reitz, R.D. “Effects of Drop Drag and Breakup on Fuel Sprays” SAE Paper 1993
- Liu, A.B. Reitz, R.D. “Mechanisms of Air-Assisted Liquid Atomization,” Atomization and Sprays 3 1 21 1992
- Reitz, R.D. “Modeling Atomization Process in High-Pressure Vaporizing Sprays,” Atomization and Spray Technology 3 309 337 1987
- O'Rourke, P.J. Amsden, A.A. “The TAB Method for Numerical Calculation of Spray Droplet Breakup,” SAE Paper 872089 1987
- Kong, S.-c. Reitz, R.D. “Multidimensional Modeling of Diesel Ignition and Combustion Using A Multistep Kinetics Models,” ASME Internal Combustion Engine Symposium, Energy-sources Technology Conference and Exhibition January 31 February 4 1993 Houston, TX
- Kong, S.-C. Ayoub, N. Reitz, R.D. “Modeling Combustion in Compression Ignition Homogeneous Charge Engines,” SAE Paper 920512 1992
- Reitz, R.D. “Assessment of Wall Heat Transfer Models for Premixed-Charge Engine Combustion Computations,” SAE Paper 910267 1991
- Kuo, T.-W. Reitz, R.D. “Computations of Premixed-Charge Combustion in Pancake and Pent-roof Engines,” SAE Paper 890670 1989
- Kuo, T.-W. Reitz, R.D. “Three-Dimensional Computations of Combustion in Premixed-Charge and Fuel-injected Two-Stroke Engines,” SAE Paper 920425 1992
- Halstead, M. Kirsh, L. Quinn, C. “The Autoignition of Hydrocarbon Fuels at High Temperatures and Pressures - Fitting of a Mathematical Model,” Combustion and Flame 30 45 60 1977
- Yan, J. Borman, G.L. “Analysis and in-cylinder measurement of particulate radiant emissions and temperature in a direct injection diesel engine,” SAE Paper 881315 1988
- Gentry, R.A. Daly, B.J. Amsden, A.A. “KIVA-COAL: A Modified Version of the KIVA Program for Calculating the Combustion Dynamics of a Coal-Water Slurry in a Diesel Engine Cylinder,” Los Alamos National Laboratory Report LA-1 1045-MS August 1987
- Surovokin, V.F. “Analytical Description of the Processes of Nucleus-formation and Growth of Particles of Carbon Black in the Thermal Decomposition of Aromatic Hydrocarbons in the Gas Phase,” Solid Fuel Chemistry 10 92 101 1976
- Nagle, J. Strickland-Constable, R.F. “Oxidation of Carbon between 1000-2000 C” Proc. of the Fifth Carbon Conf. 1 Pergammon Press 154 1962
- Heywood, J. B. “Pollutant Formation and Control in Spark-ignition Engines,” Progress in Energy and Combustion Science 1 135 164 1976
- Rutland, C.J. Pieper, C. Hessel, R. “Intake and Cylinder Flow Modeling with a Dual-Valve Port,” SAE Paper 1993
- Steinbrenner, J.P. Chawner, J.R. Fouts, C.L. “The Gridgen 3D Multiple Block Grid Generation System,” Flight Dynamics Laboratory Report Wright-Patterson Air Force Base 1990