Aerosol dynamic processes of soot aggregates in a laminar ethene diffusion flame

Puri, Rahul; Richardson, Thomas F.; Santoro, Robert J.; Dobbins, Richard A.

doi:10.1016/0010-2180(93)90043-3

Cited by 234 publications

(117 citation statements)

References 18 publications

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“…It is interesting to see that the only experimental predictions that match our numerical conclusions belong to Cai et al (1995). Relevant (or not) to this comparison, their aggregates were generated from a methane oxygen enriched ame while the remaining authors-namely, Köylü et al (1995a), Puri et al (1993), and Megaridis and Dobbins (1990)-used either acetylene or ethylene nonpremixed ames, i.e., heavy sooting ames. It would be interesting to compare the morphology, in particular, the differences of partial sintering that may exist between these aggregates.…”

Section: A M Brasil Et Almentioning

confidence: 54%

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Evaluation of the Fractal Properties of Cluster?Cluster Aggregates

Brasil¹,

Farias²,

Carvalho³

2000

Aerosol Science and Technology

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ABSTRACT. While the fractal dimension of cluster -cluster aggregates, D f , appears to be a well-established property, the fractal prefactor, kg (also known as structural coef cient), continues to exhibit a large range of possible values. In the present paper, an attempt is made to clarify this issue which leads to conclusive results concerning the value to adopt for the fractal prefactor of simulated aggregates. Starting from a large population of "free" numerically simulated aggregates (i.e., where no restrictions to aggregate formation were imposed) the fractal properties obtained were estimated both using morphological concepts as well as light scattering theories. Furthermore, studies for aggregates having prede ned morphological k g values (namely, k g > 2 and ca. 1) were also performed in order to check the viability of these values. The results obtained for the three different populations of aggregates considered were used to infer, through a best-t analysis, the fractal properties. Our best estimates are k g ¼ 1.27 and D f ¼ 1.82, which are approximately independent of aggregate size and composition. These results are in very good agreement with numerical predictions reported by previous authors. However, experimental results systematically indicate k g > 2. This motivated the present authors to identify possible reasons for these large discrepancies. Present calculations indicate that partial sintering in conjunction with the polydispersity of aggregates (resulting in a cut-off function coef cient, k p , >1) contributes to a systematic increase in k g , possibly justifying the differences between numerical and experimental results.

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Section: A M Brasil Et Almentioning

confidence: 54%

“…Köylü et al (1995b ) 3-D TEM 2.71 1.65 Köylü et al (1995b ) 2-D TEM 2.39 1.67 Köylü et al (1995b ) 2-D TEM 2.35 1.66 Köylü et al (1995b ) 2-D TEM 2.17 1.73 Köylü et al (1995b ) 2-D TEM 2.18 1.54 Puri et al (1993) ALS 3.50 1. 40 Cai et al (1995) 3-D TEM 1.23 1.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the Fractal Properties of Cluster?Cluster Aggregates

Brasil¹,

Farias²,

Carvalho³

2000

Aerosol Science and Technology

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“…premixed Sorensen et al (1992a,b) CH,/O, premixed Koylu & Faeth (1992) Many fuels large scale Puri et al (1993) C,H, Diff. Cai et al (1993) CH,/O, premixed Koylu & Faeth (1994a, b) Many fuels large scale Cai et al (1995) CH,/O, premixed Koyiu et al (1995) C acetylene/air diffusion flames, polystyrene flames, and diesel emissions.…”

Section: Introductionmentioning

confidence: 99%

“…Considerable effort has been made to study the morphology of soot aggregates that are produced by hydrocarbon flames Heckman, 1967, 1969;Forrest and Witten, 1979;Samson et al, 1987;Bourrat et al, 1988;Zhang et al, 1988;Megaridis and Dobbins, 1990;Gangopadhyay et al, 1991;Charalampopoulos and Chang, 1991;Sorensen et al, 1992aSorensen et al, , 1992bPuri et al, 1993;Cai et al, 1993Cai et al, , 1995Koylu et al, 1992Koylu et al, , 1994aKoylu et al, , 1994bKoylu et al, , 1995. Consequently, it is now well established that these aggregates are composed of small, on the order of a few tens of nanometers, primary particles which are randomly clustered together.…”

Section: Introductionmentioning

confidence: 99%

The Morphology of Macroscopic Soot

Sorensen

Feke

1996

Aerosol Science and Technology

103

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ABSTRACT. The morphology of soot collected from a laminar acetylenelair diffusion flame was studied. Collection methods included both thermophoretic and impaction sampling from both the luminous and nonluminous portions of the flow. The soot was viewed with both electron and optical microscopy. Cluster sizes ranged over four orders of magnitude from 50 nm to 400 p m to include some clusters visible to the naked eye. A new method of micrograph analysis, necessary when the clusters were large, was developed to account for the unresolved primary particles. Over this entire size range, the same fractal morphology was found with a fractal dimension of D = 1.8 and, within a rather large uncertainty, the same prefactor k,= 1.7. Thus, the fractal morphology of soot remains constant from clusters of about 10 primary particles per aggregate to macroscopic clusters of over

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“…A number of diffusion flame experimental studies [13][14][15][16][17] have looked at the detailed structure of soot aggregates including the primary particle diameter, primary particle number density, number of primary particles per aggregate and the fractal dimension of soot aggregates. Modelling soot aggregate nanostructure and size distribution in laminar diffusion flames requires adding to the flame code the detailed fixed sectional aerosol dynamics model [11,12].…”

Section: Introductionmentioning

confidence: 99%

Implementation of an advanced fixed sectional aerosol dynamics model with soot aggregate formation in a laminar methane/air coflow diffusion flame

Zhang

Guo

Liu

et al. 2008

Combustion Theory and Modelling

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/npsi/ctrl?action=rtdoc&an=3535848&lang=en http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?action=rtdoc&an=3535848&lang=frAccess and use of this website and the material on it are subject to the Terms and Conditions set forth at http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/jsp/nparc_cp.jsp?lang=en NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur. For the publisher's version, please access the DOI link below./ Pour consulter la version de l'éditeur, utilisez le lien DOI ci-dessous.http://dx.doi.org/10.1080/13647830801966153Combustion Theory and Modelling, 12, 4, pp. 621-641, 2008 Implementation of an advanced fixed sectional aerosol dynamics model with soot aggregate formation in a laminar methane/air coflow diffusion flame Zhang, Q.; Guo, Hongsheng; Liu, Fengshan; Smallwood, Gregory J.; Thomson, M.J. Full terms and conditions of use: http://www.informaworld.com/terms-and-conditions-of-access.pdf This article may be used for research, teaching and private study purposes. Any substantial or systematic reproduction, re-distribution, re-selling, loan or sub-licensing, systematic supply or distribution in any form to anyone is expressly forbidden. PLEASE SCROLL DOWN FOR ARTICLEThe publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date. The accuracy of any instructions, formulae and drug doses should be independently verified with primary sources. The publisher shall not be liable for any loss, actions, claims, proceedings, demand or costs or damages whatsoever or howsoever caused arising directly or indirectly in connection with or arising out of the use of this material. Vol. 12, No. 4, August 2008, 621-641 An advanced fixed sectional aerosol dynamics model describing the evolution of soot particles under simultaneous nucleation, coagulation, surface growth and oxidation processes is successfully implemented to model soot formation in a two-dimensional laminar axisymmetric coflow methane/air diffusion flame. This fixed sectional model takes into account soot aggregate formation and is able to provide soot aggregate and primary particle size distributions. Soot nucleation, surface growth and oxidation steps are based on the model of Fairweather et al. Soot equations are solved simultaneously to ensure convergence. The numerically calculated flame temperature, species concentrations and soot volume fraction are in good agreement with the experimental data in the literature. The structures of soot aggregates are determined by the nucleation, coagulation, surface growth and oxidation processes. The result of the soot aggregate size distribution function shows that the aggregate number density is dominated by small aggregates while the a...

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Aerosol dynamic processes of soot aggregates in a laminar ethene diffusion flame

Cited by 234 publications

References 18 publications

Evaluation of the Fractal Properties of Cluster?Cluster Aggregates

Evaluation of the Fractal Properties of Cluster?Cluster Aggregates

The Morphology of Macroscopic Soot

Implementation of an advanced fixed sectional aerosol dynamics model with soot aggregate formation in a laminar methane/air coflow diffusion flame

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