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Implementation and validation of a new soot model and application to aeroengine combustors

Balthasar, Michael LU ; Mauss, Fabian LU ; Pfitzner, M and Mack, A (2002) In Journal of Engineering for Gas Turbines and Power 124(1). p.66-74
Abstract
The modeling of soot formation and oxidation under industrially relevant conditions has made significant progress in recent years. Simplified models introducing a small number of transport equations into a CFD Code have been used with some success in research configurations simulating a reciprocating diesel engine. Soot formation and oxidation in the turbulent flow is calculated on the basis of a laminar flamelet library model. The gas phase reactions are modeled with a detailed mechanism for the combustion of heptane containing 89 species and 855 reactions developed by Frenklach and Warnatz and revised by Mauss. The soot model is divided into gas phase reactions. the growth of polycyclic aromatic hydrocarbons (PAH) and the processes of... (More)
The modeling of soot formation and oxidation under industrially relevant conditions has made significant progress in recent years. Simplified models introducing a small number of transport equations into a CFD Code have been used with some success in research configurations simulating a reciprocating diesel engine. Soot formation and oxidation in the turbulent flow is calculated on the basis of a laminar flamelet library model. The gas phase reactions are modeled with a detailed mechanism for the combustion of heptane containing 89 species and 855 reactions developed by Frenklach and Warnatz and revised by Mauss. The soot model is divided into gas phase reactions. the growth of polycyclic aromatic hydrocarbons (PAH) and the processes of particle inception, heterogeneous face growth, oxidation, and condensation. The first two are modeled within the laminar flamelet chemistry, while the soot model deals with the soot particle processes. The time scales of soot formation are assumed to he much larger than the turbulent time scales. Therefore rates of soot formation are tabulated in the flamelet libraries rather than the soot volume fraction itself. The different rates of soot formation, e.g., particle inception, sinface growth, firagmentation, and oxidation, computed on the basis of a detailed soot model, are calculated in the dissipation rate space and further simplified by fitting them to simple analytical functions. A transport equation for the mean soot mass fraction is solved in the CFD code. The mean rate in this transport equation is closed with the help of presumed probability density functions for the mixture fraction and the scalar dissipation rate. Heat loss due to radiation can be taken into account by including a heat loss parameter it? the flamelet calculations describing the change of enthalpy due to radiation, but was not used for the results reported here. The soot model was integrated into an existing commercial CFD code is a post-processing module to existing combustion CFD flow fields and is very robust with high convergence rates. The model is validated with laboratory flame data and using a realistic three-dimensional BM V Rolls-Royce combustor configuration, where test data at high pressure are available. Good agreement between experiment and simulation is achieved for laboratory flames, whereas soot is overpredicted for the aeroengine combustor configuration by 1-2 orders of magnitude. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Engineering for Gas Turbines and Power
volume
124
issue
1
pages
66 - 74
publisher
American Society of Mechanical Engineers
external identifiers
  • wos:000175336100009
  • scopus:0036008715
ISSN
1528-8919
DOI
10.1115/1.1377596
language
English
LU publication?
yes
id
f8601fdf-119c-48ae-8617-0a767808bbb1 (old id 339547)
date added to LUP
2007-08-08 08:50:03
date last changed
2017-10-22 03:48:37
@article{f8601fdf-119c-48ae-8617-0a767808bbb1,
  abstract     = {The modeling of soot formation and oxidation under industrially relevant conditions has made significant progress in recent years. Simplified models introducing a small number of transport equations into a CFD Code have been used with some success in research configurations simulating a reciprocating diesel engine. Soot formation and oxidation in the turbulent flow is calculated on the basis of a laminar flamelet library model. The gas phase reactions are modeled with a detailed mechanism for the combustion of heptane containing 89 species and 855 reactions developed by Frenklach and Warnatz and revised by Mauss. The soot model is divided into gas phase reactions. the growth of polycyclic aromatic hydrocarbons (PAH) and the processes of particle inception, heterogeneous face growth, oxidation, and condensation. The first two are modeled within the laminar flamelet chemistry, while the soot model deals with the soot particle processes. The time scales of soot formation are assumed to he much larger than the turbulent time scales. Therefore rates of soot formation are tabulated in the flamelet libraries rather than the soot volume fraction itself. The different rates of soot formation, e.g., particle inception, sinface growth, firagmentation, and oxidation, computed on the basis of a detailed soot model, are calculated in the dissipation rate space and further simplified by fitting them to simple analytical functions. A transport equation for the mean soot mass fraction is solved in the CFD code. The mean rate in this transport equation is closed with the help of presumed probability density functions for the mixture fraction and the scalar dissipation rate. Heat loss due to radiation can be taken into account by including a heat loss parameter it? the flamelet calculations describing the change of enthalpy due to radiation, but was not used for the results reported here. The soot model was integrated into an existing commercial CFD code is a post-processing module to existing combustion CFD flow fields and is very robust with high convergence rates. The model is validated with laboratory flame data and using a realistic three-dimensional BM V Rolls-Royce combustor configuration, where test data at high pressure are available. Good agreement between experiment and simulation is achieved for laboratory flames, whereas soot is overpredicted for the aeroengine combustor configuration by 1-2 orders of magnitude.},
  author       = {Balthasar, Michael and Mauss, Fabian and Pfitzner, M and Mack, A},
  issn         = {1528-8919},
  language     = {eng},
  number       = {1},
  pages        = {66--74},
  publisher    = {American Society of Mechanical Engineers},
  series       = {Journal of Engineering for Gas Turbines and Power},
  title        = {Implementation and validation of a new soot model and application to aeroengine combustors},
  url          = {http://dx.doi.org/10.1115/1.1377596},
  volume       = {124},
  year         = {2002},
}