This content is not included in your SAE MOBILUS subscription, or you are not logged in.
Simulation and Comparison of Autoignition of Homogeneous Fuel/Air Mixtures and Sprays in Diesel Engines
Technical Paper
2016-01-0311
ISSN: 0148-7191,
e-ISSN: 2688-3627
Annotation ability available
Sector:
Language:
English
Abstract
All previous correlations of the ignition delay (ID) period in diesel combustion show a positive activation energy, which means that shorter ID periods are achieved at higher charge temperatures. This is not the case in the autoignition of most homogeneous hydrocarbons-air mixtures where they experience the NTC (Negative Temperature Coefficient ) regime in the intermediate temperature range, from about 800 K to 1000 K). Here, the autoignition reactions slow down and longer ID periods are experienced at higher temperatures. Accordingly the global activation energy for the autoignition reactions of homogeneous mixtures should vary from positive to negative values. In this paper, the discrepancy in the autoignition of a homogeneous charge and a heterogeneous charge is investigated. 3-D computer simulations of the physical and chemical processes in the combustion of fuel sprays in a diesel engine showed that this discrepancy is caused by the variations in the equivalence ratio of the first ignitable site in the spray with charge temperature. This finding has been validated by the simulation of autoignition of a homogeneous mixture at different equivalence ratios.
Authors
Topic
Citation
Joshi, U., Trivedi, M., Zheng, Z., Schihl, P. et al., "Simulation and Comparison of Autoignition of Homogeneous Fuel/Air Mixtures and Sprays in Diesel Engines," SAE Technical Paper 2016-01-0311, 2016, https://doi.org/10.4271/2016-01-0311.Also In
References
- Wolfer H. H., "Ignition Lag in the Diesel Engine," VDI --- Forschumgshelft(392), 1938.
- Elliott, M., "Combustion of Diesel Fuel," SAE Technical Paper 490213, 1949, doi:10.4271/490213.
- Sitkei G., "Uber den dieselmotorisehen Zundverzug," M . T . Z . , Jahrg 24, Heft 6, 1963.
- Henein N. A., and Bolt J. A., "The Effect of Some Engine Variables on Ignition Delay and Other Combustion Phenomena in a Diesel Engine," Proceedings of the Institution of Mechanical Engineers, 184(310), pp. 130-136, 1969.
- Henein, N. and Bolt, J., "Correlation of Air Charge Temperature and Ignition Delay for Several Fuels in a Diesel Engine," SAE Technical Paper 690252, 1969, doi:10.4271/690252.
- Pedersen, P. and Qvale, B., "A Model for the Physical Part of the Ignition Delay in a Diesel Engine," SAE Technical Paper 740716, 1974, doi:10.4271/740716.
- Kwon Soon-Ik, Arai M., and Hiroyasu H., "Effect of Temperature and Pressure on Ignition Delay in Direct Injection Diesel Engine," MESJ, 24, 1990.
- Jayakumar C., "Effect Of Intake Temperature And Boost Pressure On The Auto-Ignition Of Fuels With Different Cetane Numbers And Volatilities," PhD, Wayne State University, Detroit, 2013.
- Zheng Z., "Effect of Cetane Number and Volatility on Autoignition and Combustion of Alternative Fuels and Their Surrogates," PhD, Wayne State University, Detroit, 2014.
- "CONVERGE theory manual Version 2.1.0," CONVERGE Science Inc., 2013.
- Joshi U., “Quantification of Auto-Ignition in Diesel Engines,” PhD, Wayne State University, Detroit, 2015.
- Mtui, P. and Hill, P., "Ignition Delay and Combustion Duration with Natural Gas Fueling of Diesel Engines," SAE Technical Paper 961933, 1996, doi:10.4271/961933.
- Ouellette, P., Mtui, P., and Hill, P., "Numerical Simulations of Directly Injected Natural Gas and Pilot Diesel Fuel in a Two-Stroke Compression Ignition Engine," SAE Technical Paper 981400, 1998, doi:10.4271/981400.
- Naber, J. D., et al., "Effects of natural gas composition on ignition delay under diesel conditions," Combustion and Flame 99.2 (1994): 192-200.
- Tao, F. and Chomiak, J., "Numerical Investigation of Reaction Zone Structure and Flame Liftoff of DI Diesel Sprays with Complex Chemistry," SAE Technical Paper 2002-01-1114, 2002, doi:10.4271/2002-01-1114.
- Halstead, M. P., Kirsch L. J., and Quinn C. P., "The autoignition of hydrocarbon fuels at high temperatures and pressures-fitting of a mathematical model," Combustion and flame 30 (1977): 45-60.
- Fuchs, T. and Rutland, C., "Intake Flow Effects on Combustion and Emissions in a Diesel Engine," SAE Technical Paper 980508, 1998, doi:10.4271/980508.
- Kamimoto, T., Akiyoshi, M., and Kosaka, H., "A Numerical Simulation of Ignition Delay in Diesel Engines," SAE Technical Paper 980501, 1998, doi:10.4271/980501.
- Kong, S., Han, Z., and Reitz, R., "The Development and Application of a Diesel Ignition and Combustion Model for Multidimensional Engine Simulation," SAE Technical Paper 950278, 1995, doi:10.4271/950278.
- Tap, F. A., and Veynante Denis, "Simulation of flame lift-off on a diesel jet using a generalized flame surface density modeling approach," Proceedings of the Combustion Institute 30.1 (2005): 919-926.
- Stapf, P., et al., "A Numerical Study of Heating, Mixture Formation, and Detailed Combustion around a Fuel Droplet under Engine-Like Conditions," International Symposium COMODIA. Vol. 94. 1994.
- Wan, Y., Pitsch, H., and Peters, N., "Simulation of Autoignition Delay and Location of Fuel Sprays Under Diesel-Engine Relevant Conditions," SAE Technical Paper 971590, 1997, doi:10.4271/971590.