Towards a detailed soot model for internal combustion engines
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Pembroke Street, Cambridge CB2 3RA (United Kingdom)
- Department of Chemical Engineering, University of Utah, 1495 East 100 South, Kennecott Research Building, Salt Lake City, UT 84112 (United States)
- Frontier Research Center, Toyota Central R and D Labs., Inc., Nagakute, Aichi 480-1192 (Japan)
- Higashifuji Technical Center, Toyota Motor Corporation, Mishuku 1200, Susono, Shizuoka 480-1193 (Japan)
In this work, we present a detailed model for the formation of soot in internal combustion engines describing not only bulk quantities such as soot mass, number density, volume fraction, and surface area but also the morphology and chemical composition of soot aggregates. The new model is based on the Stochastic Reactor Model (SRM) engine code, which uses detailed chemistry and takes into account convective heat transfer and turbulent mixing, and the soot formation is accounted for by SWEEP, a population balance solver based on a Monte Carlo method. In order to couple the gas-phase to the particulate phase, a detailed chemical kinetic mechanism describing the combustion of Primary Reference Fuels (PRFs) is extended to include small Polycyclic Aromatic Hydrocarbons (PAHs) such as pyrene, which function as soot precursor species for particle inception in the soot model. Apart from providing averaged quantities as functions of crank angle like soot mass, volume fraction, aggregate diameter, and the number of primary particles per aggregate for example, the integrated model also gives detailed information such as aggregate and primary particle size distribution functions. In addition, specifics about aggregate structure and composition, including C/H ratio and PAH ring count distributions, and images similar to those produced with Transmission Electron Microscopes (TEMs), can be obtained. The new model is applied to simulate an n-heptane fuelled Homogeneous Charge Compression Ignition (HCCI) engine which is operated at an equivalence ratio of 1.93. In-cylinder pressure and heat release predictions show satisfactory agreement with measurements. Furthermore, simulated aggregate size distributions as well as their time evolution are found to qualitatively agree with those obtained experimentally through snatch sampling. It is also observed both in the experiment as well as in the simulation that aggregates in the trapped residual gases play a vital role in the soot formation process. (author)
- OSTI ID:
- 21177443
- Journal Information:
- Combustion and Flame, Vol. 156, Issue 6; Other Information: Elsevier Ltd. All rights reserved; ISSN 0010-2180
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
33 ADVANCED PROPULSION SYSTEMS
INTERNAL COMBUSTION ENGINES
SOOT
POLYCYCLIC AROMATIC HYDROCARBONS
DISTRIBUTION FUNCTIONS
SYNTHESIS
HEPTANE
PYRENE
CHEMICAL REACTIONS
COMBUSTION KINETICS
MONTE CARLO METHOD
SIMULATION
CONVECTION
TURBULENCE
PARTICLE SIZE
SURFACE AREA
COUPLING
GASES
HEAT
PARTICULATES
CHEMICAL COMPOSITION
MASS NUMBER
STOCHASTIC PROCESSES
COMPRESSION
TIME DEPENDENCE
IGNITION
MASS
MIXING
MORPHOLOGY
PRECURSOR