Large eddy simulation of soot formation in a turbulent non-premixed jet flame

Journal Article · Sun Feb 15 04:00:00 EST 2009 · Combustion and Flame

DOI:https://doi.org/10.1016/J.COMBUSTFLAME.2008.09.003· OSTI ID:21137923

El-Asrag, Hossam ^[1]; Menon, Suresh ^[2]

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1. Center For Turbulence Research, Stanford, CA 94305 (United States)
2. School of Aerospace Engineering, Georgia Institute of Technology, Atlanta, GA 30332 (United States)

A recently developed subgrid model for soot dynamics [H. El-Asrag, T. Lu, C.K. Law, S. Menon, Combust. Flame 150 (2007) 108-126] is used to study the soot formation in a non-premixed turbulent flame. The model allows coupling between reaction, diffusion and soot (including soot diffusion and thermophoretic forces) processes in the subgrid domain without requiring ad hoc filtering or model parameter adjustments. The combined model includes the entire process, from the initial phase, when the soot nucleus diameter is much smaller than the mean free path, to the final phase, after coagulation and aggregation, where it can be considered in the continuum regime. A relatively detailed but reduced kinetics for ethylene-air is used to simulate an experimentally studied non-premixed ethylene/air jet diffusion flame. Acetylene is used as a soot precursor species. The soot volume fraction order of magnitude, the location of its maxima, and the soot particle size distribution are all captured reasonably. Along the centerline, an initial region dominated by nucleation and surface growth is established followed by an oxidation region. The diffusion effect is found to be most important in the nucleation regime, while the thermophoretic forces become more influential downstream of the potential core in the oxidation zone. The particle size distribution shows a log-normal distribution in the nucleation region, and a more Gaussian like distribution further downstream. Limitations of the current approach and possible solution strategies are also discussed. (author)

• OSTI ID: 21137923
• Journal Information: Combustion and Flame, Journal Name: Combustion and Flame Journal Issue: 2 Vol. 156; ISSN CBFMAO; ISSN 0010-2180
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
ACETYLENE
AGGLOMERATION
AIR
COMBUSTION KINETICS
COUPLING
DIFFUSION
DISTRIBUTION
DYNAMICS
ETHYLENE
FLAMES
JETS
Large eddy simulation
MATHEMATICAL SOLUTIONS
MOMENTS METHOD
Method of moment
NUCLEATION
OXIDATION
PARTICLE SIZE
POTENTIALS
PRECURSOR
SIMULATION
SOOT
SYNTHESIS
TURBULENCE
Turbulent flames
ZONES