Deposition and coagulation of polydisperse nanoparticles by Brownian motion and turbulence

Kim, D.S.; Hong, Sang Bum; Kim, Y.J.; Lee, K.W.

doi:10.1016/j.jaerosci.2006.07.001

Cited by 28 publications

(19 citation statements)

References 15 publications

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“…This GSD value is above the self-preserving one (1.47) for spherical particles in the free molecular regime 38 but in agreement with the self-preserving size distribution of agglomerates 39 with fractal dimension (D f ) of 2-2.3 at moderate concentrations. 41 Increasing the sampling HAB to 20 and 30 cm ( Figure 3) decreased the particle concentration in line with the increased surrounding air entrainment. 41 Increasing the sampling HAB to 20 and 30 cm ( Figure 3) decreased the particle concentration in line with the increased surrounding air entrainment.…”

Section: Resultsmentioning

confidence: 86%

“…40 Deviations from the self-preserving GSD for Brownian coagulation are also attributable to the contribution of turbulence-induced coagulation. 41 Increasing the sampling HAB to 20 and 30 cm ( Figure 3) decreased the particle concentration in line with the increased surrounding air entrainment. Furthermore, it decreased the mode and geometric mean diameter to 126 and 109 nm, respectively, while slightly increasing the GSD from 1.61 to 1.63.…”

Section: Resultsmentioning

confidence: 86%

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Flame spray pyrolysis synthesis and aerosol deposition of nanoparticle films

Tricoli

Elmøe

2012

AIChE Journal

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The assembly of nanoparticle films by flame spray pyrolysis (FSP) synthesis and deposition on temperature‐controlled substrates (323–723 K) was investigated for several application‐relevant conditions. An exemplary SnO2 nanoparticle aerosol was generated by FSP and its properties (e.g., particle size distribution), and deposition dynamics were studied in details aiming to a simple correlation between process settings and film growth rate. At high precursor concentrations (0.05–0.5·mol/L), typically used for FSP synthesis, the nanoparticles agglomerated rapidly in the aerosol leading to large (>100 nm) fractal‐like structures with low diffusivity. As a result, thermophoresis was confirmed as the dominant nanoparticle deposition mechanism down to small (≈40 K) temperature differences (ΔT) between the aerosol and the substrate surface. For moderate‐high ΔT (>120 K), thermal equilibrium was rapidly obtained yielding a constant thermophoretic flux and film growth rate. A model was developed to predict the nanoparticle deposition rates by FSP synthesis at moderate‐high ΔT that does not require detailed analysis of the aerosol composition. Comparison with previous studies having similar nozzle geometries showed that the deposition rates of FSP‐made aerosols can be reasonably well predicted for various materials and flame conditions. © 2012 American Institute of Chemical Engineers AIChE J, 2012

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Section: Resultsmentioning

confidence: 86%

Section: Resultsmentioning

confidence: 86%

Flame spray pyrolysis synthesis and aerosol deposition of nanoparticle films

Tricoli

Elmøe

2012

AIChE Journal

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“…Some researchers also conducted experimental works of Brownian coagulation to validate the theory analysis (Wagner and Kerker 1977;Kim et al 2003Kim et al , 2006. Kim et al (2006) obtained the coagulation rate from the change in the total number concentration of polydisperse sodium chloride aerosols in a closed chamber at atmospheric pressure. Experimental Brownian coagulation rates were also shown to follow Brownian coagulation in the transition regime over which the majority of particles in the study were distributed.…”

Section: Particle Coagulationmentioning

confidence: 99%

Characteristics of particle coagulation in an underground parking lot

Zhao

Kato

Zhao

2015

Environ Sci Pollut Res

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Particles in vehicle exhaust plumes in underground parking lots have adverse health effects due to the enclosed environment in which they are released and the temperature difference between the tailpipe and ambient environment; at the same time, particle coagulation might be obvious near the tailpipe in an underground parking lot. In the present study, airflow and temperature fields were calculated using the Realizable k-ε model, and the Eulerian particle transport model was selected in the numerical simulation of particle concentration dispersion. Polydisperse thermal coagulation due to Brownian collisions was employed to calculate the particle coagulation. The results show that particle coagulation rate and half-time were significant within 1 m from the tailpipe. The variations in the particle coagulation rate and half-time were similar, but their directions were opposite. Air exhaust time was nearly four times longer than averaged half-time and 40 times longer than minimum half-time. The peak particle diameter increased approximately 1.43 times due to coagulation. A double particle concentration at the tailpipe caused the fourfold rise in the particle coagulation rate in the distance ranging less than 1 m from the tailpipe. An increase in exhaust velocity at the tailpipe could shorten the obvious range of particle coagulation along the centerline of the tailpipe from 1 to 0.8 m in the study.

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“…Increasing air turbulence increases the rate of coagulation. For example, stirring a chamber with a fan could increase the rate for 100 nm particles by a factor of two (Kim et al, 2006).…”

Section: Coagulation and Scavengingmentioning

confidence: 99%

Conceptual model for assessment of inhalation exposure to manufactured nanoparticles

Schneider

Brouwer²,

Koponen

et al. 2011

J Expo Sci Environ Epidemiol

106

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As workplace air measurements of manufactured nanoparticles are relatively expensive to conduct, models can be helpful for a first tier assessment of exposure. A conceptual model was developed to give a framework for such models. The basis for the model is an analysis of the fate and underlying mechanisms of nanoparticles emitted by a source during transport to a receptor. Four source domains are distinguished; that is, production, handling of bulk product, dispersion of ready-to-use nanoproducts, fracturing and abrasion of end products. These domains represent different generation mechanisms that determine particle emission characteristics; for example, emission rate, particle size distribution, and source location. During transport, homogeneous coagulation, scavenging, and surface deposition will determine the fate of the particles and cause changes in both particle size distributions and number concentrations. The degree of impact of these processes will be determined by a variety of factors including the concentration and size mode of the emitted nanoparticles and background aerosols, source to receptor distance, and ventilation characteristics. The second part of the paper focuses on to what extent the conceptual model could be fit into an existing mechanistic predictive model for ''conventional'' exposures. The model should be seen as a framework for characterization of exposure to (manufactured) nanoparticles and future exposure modeling.

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Deposition and coagulation of polydisperse nanoparticles by Brownian motion and turbulence

Cited by 28 publications

References 15 publications

Flame spray pyrolysis synthesis and aerosol deposition of nanoparticle films

Flame spray pyrolysis synthesis and aerosol deposition of nanoparticle films

Characteristics of particle coagulation in an underground parking lot

Conceptual model for assessment of inhalation exposure to manufactured nanoparticles

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