On the relative contribution of acetylene and aromatics to soot particle surface growth

1998 ◽  
Vol 112 (1-2) ◽  
pp. 270-274 ◽  
Author(s):  
Andrei Kazakov ◽  
Michael Frenklach
Keyword(s):  
Soot Particle ◽  
Particle Surface ◽  
Surface Growth ◽  
Relative Contribution

Simulation of Soot Size Distribution in a Counterflow Flame

2015 ◽  
Vol 13 (1) ◽  
pp. 95-101 ◽  
Author(s):  
Z. He ◽  
K. Zhou ◽  
M. Xiao ◽  
F. Wei
Keyword(s):  
Size Distribution ◽  
Fossil Fuels ◽  
Soot Particle ◽  
Soot Formation ◽  
Health Hazard ◽  
Hydrogen Abstraction ◽  
Surface Growth ◽  
Narrow Region ◽  
Counterflow Flame ◽  
The Rich

Abstract Soot formed during the rich combustion of fossil fuels is an undesirable pollutant and health hazard. A newly developed Monte Carlo method is used to simulate the soot formation in a counterflow diffusion flame of ethylene. The simulation uses a new reaction mechanism available in literature, which focuses on modeling the formation of large polycyclic aromatic hydrocarbons (PAHs) up to coronene (C24H12). Nascent soot particles are assumed to form from the collision of eight different PAH molecules. Soot surface growth includes the hydrogen-abstraction-C2H2-addition mechanism and the condensation of the PAHs. Soot coagulation is in the free-molecular regime because particles are small (not more than a hundred nanometer). The coupling between vapor consumption and soot formation is handled by an interpolative moment method. Soot particle diffusion is found negligible throughout the counterflow flame, except for a very narrow region right around the stagnation plane. The soot particle size distribution (PSD) generally exhibits a bimodal shape. The first peak corresponds to a large number of nascent particles, while the second peak results from the competition between nucleation and coagulation. Surface growth affects the PSD quantitatively, but does not change the modality. A comparison with experimental data is also provided.

The Effects of Nucleation on Soot Dynamic Evolution Based on the Method of Moments

2014 ◽  
Vol 529 ◽  
pp. 232-236
Author(s):  
Jin Ping Liu ◽  
Ming Rui Wei ◽  
He Lin Xiao ◽  
Fei Peng
Keyword(s):  
Numerical Model ◽  
Method Of Moments ◽  
Soot Particle ◽  
Combustion Process ◽  
Particle Growth ◽  
Surface Growth ◽  
Particle Nucleation ◽  
Growth Processes ◽  
Chemical Kinetic Model ◽  
Growth Evolution

The mathematical model of soot dynamical evolution process is built based on the discrete particles population balance theory, including particle nucleation, collision coagulation, oxidation and surface growth processes; a corresponding numerical model is established using Lagrange interpolation method of moments. Based on the perfectly-stirred reactor combustion model, coupled the numerical model with detailed chemical kinetic model. The computing platform of soot particle growth evolution is established. Meanwhile, three nucleation models are built for the soot nucleation in this paper. Two chemical reaction mechanisms are used to study different fuels combustion process. The related information of soot particle growth evolution is obtained, the effect of different nucleation model on other dynamical events such as coagulation, oxidation and surface growth processes is discussed.

Soot Particle Evolution and Transport in a Direct Injection Diesel Engine

2015 ◽  
Vol 74 (3) ◽  
Author(s):  
Muhammad Ahmar Zuber ◽  
Wan Mohd Faizal Wan Mahmood ◽  
Zambri Harun ◽  
Zulkhairi Zainol Abidin
Keyword(s):  
Particle Size ◽  
Soot Particle ◽  
Soot Formation ◽  
Formation Rate ◽  
Soot Oxidation ◽  
Surface Growth ◽  
Number Density ◽  
Coagulation Rate ◽  
Particulate Emission ◽  
Soot Particles

Particle-based in-cylinder soot distribution study is becoming more important as the rules and regulations pertaining to particulate emission of diesel-powered vehicles have been increasingly more stringent. This paper focuses on the investigation of soot size evolution and its distribution and transport inside an engine cylinder. The overall process of soot formation includes soot nucleation, surface growth, oxidation, coagulation and agglomeration. The present study considers only soot surface growth, oxidation and coagulation to predict the in-cylinder soot particle size. The soot surface growth model was based on Hiroyasu’s soot formation model while soot oxidation was referred to Nagle & Strickland-Constable’s soot oxidation model. Coagulation rate was defined using Smoluchowski’s equation with constant proposed by Wersborg. From this study, it is demonstrated that soot particles with relatively larger size are gathered in the centre of the cylinder while smaller soot particles are found to be in the region near the wall. Soot number density is considerably high at the start of combustion and reduces sharply afterward while the soot particle size shows the opposite trend. Soot formation rate was found to be dominant at earlier crank angle and is overcome by soot oxidation and coagulation processes that caused lower soot number density but higher soot particle size.  

scholarly journals Ice nucleation activities of soot particles internally mixed with sulphuric acid at cirrus cloud conditions

2021 ◽  
Author(s):  
Kunfeng Gao ◽  
Chong-Wen Zhou ◽  
Eszter J. Barthazy Meier ◽  
Zamin A. Kanji
Keyword(s):  
Electron Microscopy ◽  
Sulphuric Acid ◽  
Soot Particle ◽  
Particle Surface ◽  
Ice Nucleation ◽  
Cloud Formation ◽  
Cirrus Cloud ◽  
Scanning Mobility Particle Sizer ◽  
Soot Particles ◽  
Two Samples

Abstract. Soot particles are important candidates for ice nucleating particles (INPs) in cirrus cloud formation which is known to exert a warming effect on climate. Bare soot particles, generally hydrophobic and fractal, mainly exist near emission sources. Coated or internally mixed soot particles are more abundant in the atmosphere and have a higher probability to impact cloud formation and climate. However, the ice nucleation ability of coated soot particles is not as well understood as that of freshly produced soot particles. In this study, two samples, a propane (C3H8) flame soot and a commercial carbon black were coated with varying wt % of sulphuric acid (H2SO4). The ratio of coating material mass to the mass of bare soot particle was controlled and progressively increased from less than 5 wt % to over 100 wt %. Both bare and coated soot particle ice nucleation activities were investigated with a continuous flow diffusion chamber operated at mixed-phase and cirrus cloud conditions. The mobility size and mass distribution of size selected soot particles with/without H2SO4 coating were measured by a scanning mobility particle sizer (SMPS) and a centrifugal particle mass analyser (CPMA) running in parallel. The mixing state and morphology of soot particles were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In addition, the evidence for the presence of H2SO4 on coated soot particle surface is shown by Energy Dispersive X-ray spectroscopy (EDX). Our study demonstrates that H2SO4 coatings suppress the ice nucleation activity of soot particles to varying degrees depending on the coating thickness, but in a non-linear fashion. Thin coatings causing pore filling in the soot-aggregate inhibits pore condensation and freezing (PCF). Thick coatings promote particle ice activation via droplet homogeneous freezing. Overall, our findings reveal that H2SO4 coatings will suppress soot particle ice nucleation abilities in the cirrus cloud regime, having implications for the fate of soot particles with respect to cloud formation in the upper troposphere.

scholarly journals Immersion Freezing Ability of Freshly Emitted Soot with Various Physico-Chemical Characteristics

Atmosphere ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1173
Author(s):  
John Falk ◽  
Kimmo Korhonen ◽  
Vilhelm B. Malmborg ◽  
Louise Gren ◽  
Axel C. Eriksson ◽  
...  
Keyword(s):  
Soot Particle ◽  
Particle Density ◽  
Particle Surface ◽  
Chemical Properties ◽  
Biomass Combustion ◽  
Soot Particles ◽  
Physico Chemical ◽  
Effective Particle ◽  
Wide Range ◽  
Immersion Freezing

The immersion freezing ability of soot particles has in previous studies been reported in the range of low/insignificant to very high. The aims of this study were to: (i) perform detailed physico-chemical characterisation of freshly produced soot particles with very different properties, (ii) investigate the immersion freezing ability of the same particles, and (iii) investigate the potential links between physico-chemical particle properties and ice-activity. A miniCAST soot generator was used to produce eight different soot samples representing a wide range of physico-chemical properties. A continuous flow diffusion chamber was used to study each sample online in immersion mode over the temperature (T) range from −41 to −32 °C, at a supersaturation of about 10% with respect to liquid water. All samples exhibited low to no heterogeneous immersion freezing. The most active sample reached ice-activated fractions (AF) of 10−3 and 10−4 at temperatures of 1.7 and 1.9 K , respectively, above the homogeneous freezing temperature. The samples were characterized online with respect to a wide range of physico-chemical properties including effective particle density, optical properties, particle surface oxidation and soot maturity. We did observe indications of increasing immersion freezing ice-activity with increasing effective particle density and increasing particulate PAH fraction. Hence, those properties, or other properties co-varying with those, could potentially enhance the immersion freezing ice-activity of the studied soot particle types. However, we found no significant correlation between the physico-chemical properties and the observed ice-nucleating ability when the particle ensemble was extended to include previously published results including more ice-active biomass combustion soot particles. We conclude that it does not appear possible in general and in any straightforward way to link observed soot particle physico-chemical properties to the ice-nucleating ability using the online instrumentation included in this study. Furthermore, our observations support that freshly produced soot particles with a wide range of physico-chemical properties have low to insignificant immersion freezing ice-nucleating ability.

A soot particle surface reactivity model applied to a wide range of laminar ethylene/air flames

2014 ◽  
Vol 161 (12) ◽  
pp. 3191-3200 ◽  
Author(s):  
Armin Veshkini ◽  
Seth B. Dworkin ◽  
Murray J. Thomson
Keyword(s):  
Soot Particle ◽  
Particle Surface ◽  
Surface Reactivity ◽  
Wide Range

Soot Formation in Propane/Air Diffusion Flames

2013 ◽  
Vol 668 ◽  
pp. 123-127 ◽  
Author(s):  
Xue Sun ◽  
D.W. Zhang ◽  
G.L. Ning
Keyword(s):  
Particle Size ◽  
Soot Particle ◽  
Rate Coefficient ◽  
Diffusion Flames ◽  
Soot Formation ◽  
Surface Growth ◽  
Wide Range ◽  
Air Diffusion

Soot formation and growth in propane/air diffusion flames in a wide range of mole ratio of propane to air from 0.01 to 0.1 have been studied experimentally and theoretically. The concentration of acetylene, soot yield and particle size have been measured and the growth of soot particle has been simulated from surface growth and nucleation processes. The rate coefficient of surface growth has been correlated with the mole ratio of propane to air and the comparisons of particle size between measured and calculated results have been made.

Surface Growth and Soot Particle Reactivity

1990 ◽  
Vol 72 (1-3) ◽  
pp. 67-77 ◽  
Author(s):  
STEPHEN J. HARRIS
Keyword(s):  
Soot Particle ◽  
Surface Growth

Optical Measurements of Soot Particles in Flames

1988 ◽  
Vol 117 ◽  
Author(s):  
Robert J. Santoro
Keyword(s):  
Surface Area ◽  
Diffusion Flames ◽  
Particle Surface ◽  
Diagnostic Techniques ◽  
Surface Growth ◽  
Optical Measurements ◽  
Particle Surface Area ◽  
Soot Particles ◽  
Laminar Diffusion Flames ◽  
Significant Research

AbstractThe formation and growth of soot particles in combustion systems represents an area of significant research interest. Critical to progress in this area has been the development of suitable optical diagnostic techniques. Principal among these has been the utilization of laser light scattering techniques to obtain particle size and concentration information. When combined with measurements of other quantities such as the velocity, the resulting spatially and temporally resolved measurements can be used to examine particle processes such as coagulation and surface growth. In the present work, the results from studies conducted in laminar diffusion flames involving laser based measurements of the soot particle and velocity fields are reviewed. As an example of the utility of such an approach, these results are used to examine the evolution of the particle surface area for a series of simple hydrocarbon fuels. The results indicate that the available surface area varies strongly with the fuel molecular structure. However, the specific surface growth rate is observed to be similar for all the fuels studied.

Sign in / Sign up

Export Citation Format

Share Document