This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
LES Analysis of Fuel/Air Mixing and Heat Release Processes in a Diesel Spray
Technical Paper
2013-01-2537
ISSN: 0148-7191, e-ISSN: 2688-3627
Annotation ability available
Sector:
Language:
English
Abstract
Numerical calculations were performed to investigate the mixture formation, ignition, and combustion processes in a diesel spray. The spray was formed by injecting n-heptane into a constant volume vessel under high-temperature and high-pressure conditions. The fuel droplets were described by a discrete droplet model (DDM). Numerical calculations for the flow and turbulent diffusion processes were performed on the basis of large eddy simulation (LES) to describe the processes of local non-homogeneous mixture formation and heat release. The oxidation processes in the mixture were calculated by Schreiber's five-step mechanism for n-heptane. Calculations were performed for sprays formed by single-stage injection and pilot/main two-stage injection. The flame structure in a diesel spray and its temporal change were discussed using a flame index proposed by Yamashita et al. The results show that combustion of a premixture release heat around the boundary between the unburnt mixture in the upstream region and burnt mixture in the downstream region, and diffusion flame is formed in the surrounding region of the burnt mixture. The different flame structures are formed according to the surrounding gas conditions. In addition, in the pilot/main two-stage injections, the ignition delay of the main spray becomes very short and the region of premixture combustion locates upstream, which could result in larger soot emissions.
Authors
Topic
Citation
Kojima, H., Kawanabe, H., Ishiyama, T., and Furutani, H., "LES Analysis of Fuel/Air Mixing and Heat Release Processes in a Diesel Spray," SAE Technical Paper 2013-01-2537, 2013, https://doi.org/10.4271/2013-01-2537.Also In
References
- Hotta , Y. , Inayoshi , M. , Nakakita , K. , Fujiwara , K. et al. Achieving Lower Exhaust Emissions and Better Performance in an HSDI Diesel Engine with Multiple Injection SAE Technical Paper 2005-01-0928 2005 10.4271/2005-01-0928
- KAWANABE , H. and ISHIYAMA , T. Numerical Analysis of Auto-ignition Process in a Non-homogeneous Mixture SAE Technical Paper 2007-01-1864 2007 10.4271/2007-01-1864
- Hori , T. , Senda , J. , Kuge , T. , and Fujimoto , H. Large Eddy Simulation of Non-Evaporative and Evaporative Diesel Spray in Constant Volume Vessel by Use of KIVALES SAE Technical Paper 2006-01-3334 2006 10.4271/2006-01-3334
- Jhavar , R. and Rutland , C. Using Large Eddy Simulations to Study Mixing Effects in Early Injection Diesel Engine Combustion SAE Technical Paper 2006-01-0871 2006 10.4271/2006-01-0871
- Kojima , H. , Kawanabe , H. , and Ishiyama , T. LES Analysis of Mixture Formation and Combustion Processes in a Diesel Spray SAE Int. J. Engines 5 2 102 111 2011 10.4271/2011-01-1849
- Yamashita , H. , Shimada , M. , and Takeno , T. A Numerical Study on Flame Stability at the Transition Point of Jet Diffusion Flames Proceedings of Twenty-Sixth Symposium (International) on Combustion 27 34 1996
- Kawanabe , H. , Kojima , H. , and Ishiyama , T. Modeling of the Auto-ignition Process of a Non-homogeneous Mixture in a Diesel Spray for CFD SAE Technical Paper 2010-01-0357 2010 10.4271/2010-01-0357
- Liu , A. , Mather , D. , and Reitz , R. Modeling the Effects of Drop Drag and Breakup on Fuel Sprays SAE Technical Paper 930072 1993 10.4271/930072
- Amsden , A.A. , O'Rourke , P.J. , and Butler , T.D. KIVA-II: A Computer Program for Chemically Reactive Flows with Sprays Los Alamous National Laboratory Report No. LA-11560-MS 1989
- Kawasaki , K. , Shioji , M. , and Fang , F. Effects of Boundary Conditions on Jet-flows Simulated by LES Transactions of the Japan Society of Mechanical Engineers, Series B 70 691 723 728 2004
- Pitsch , H. and Steiner , H. Large-eddy simulation of a turbulent piloted methane/air diffusion flame (Sandia flame D) Physics of Fluids 12 10 2541 2554 2000
- Zhu , J. and Leschziner , M.A. A Local Oscillation-Damping Algorithm for Higher-order Convection Schemes Computer Methods in Applied Mechanics and Engineering 67 355 366 1988
- Schreiber , M. , Sakak , A.S. , and Lingens , A. A Reduced Thermokinetic Model for the Autoignition of Fuels with Variable Octane Ratings Proceedings of 25th international Symposium on Combustion 933 940 1994
- Mehl , M. , Curran , H.J. , Pitz , W.J. , and Westbrook , C.K. n-Heptane, Detailed Mechanism, Version 3 Lawrence Livermore National Laboratory https://www-pls.llnl.gov/ Jan 2011
- Williams , F.A. Combustion Theory Second Addison-Wesley Publishing Company 0-201-40777-9 69 76 1985