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The Effect of Primary Particle Polydispersity on the Morphology and Mobility Diameter of the Fractal Agglomerates in Different Flow Regimes Dastanpour, Ramin; Rogak, Steven
Abstract
Properties of colloidal and aerosol agglomerates depend on their morphology. Accurate estimation of the mobility-equivalent diameter πm in different flow regimes is essential in many industrial processes and measurements. Previous work on the hydrodynamic properties of clusters focussed on agglomerates composed of monodisperse primary particles. However aggregates formed in real processes, e.g. soot particles, are usually formed from polydisperse monomers. Using numericallygenerated agglomerates it is shown here that the radius of gyration, surface area, and mass of the agglomerates increase with primary particle polydispersity (given constant geometric mean primary particle size πpg). Here, πm is taken as the projected area-equivalent diameter for the free molecular regime; Stokesian Dynamics is used to compute πm in the continuum flow regime. For fixed number of primaries and πpg, πm increases with polydispersity in both free molecular and continuum regimes (>20% for large particles at high polydispersity). Considering an aerosol population with polydisperse primary particles, this increase is found to depend on whether the variations in primary particle size occur within aggregates or between aggregates; this can be important in the interpretation of measurements. Finally, mobility diameters are correlated with total number, median diameter and its geometric standard deviation of the primary particles.
Item Metadata
Title |
The Effect of Primary Particle Polydispersity on the Morphology and Mobility Diameter of the Fractal Agglomerates in Different Flow Regimes
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Creator | |
Date Issued |
2016-04
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Description |
Properties of colloidal and aerosol agglomerates depend on their morphology. Accurate estimation
of the mobility-equivalent diameter πm in different flow regimes is essential in many industrial
processes and measurements. Previous work on the hydrodynamic properties of clusters focussed
on agglomerates composed of monodisperse primary particles. However aggregates formed in real
processes, e.g. soot particles, are usually formed from polydisperse monomers. Using numericallygenerated
agglomerates it is shown here that the radius of gyration, surface area, and mass of the
agglomerates increase with primary particle polydispersity (given constant geometric mean
primary particle size πpg). Here, πm is taken as the projected area-equivalent diameter for the free
molecular regime; Stokesian Dynamics is used to compute πm in the continuum flow regime. For
fixed number of primaries and πpg, πm increases with polydispersity in both free molecular and
continuum regimes (>20% for large particles at high polydispersity). Considering an aerosol
population with polydisperse primary particles, this increase is found to depend on whether the
variations in primary particle size occur within aggregates or between aggregates; this can be
important in the interpretation of measurements. Finally, mobility diameters are correlated with
total number, median diameter and its geometric standard deviation of the primary particles.
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Subject | |
Genre | |
Type | |
Language |
eng
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Date Available |
2018-04-01
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Provider |
Vancouver : University of British Columbia Library
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Rights |
Attribution-NonCommercial-NoDerivatives 4.0 International
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DOI |
10.14288/1.0314550
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URI | |
Affiliation | |
Citation |
Dastanpour R, Rogak SN. The effect of primary particle polydispersity on the morphology and mobility diameter of the fractal agglomerates in different flow regimes. J Aerosol Sci. 2016;94:22-32.
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Publisher DOI |
10.1016/j.jaerosci.2015.12.005
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Peer Review Status |
Reviewed
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Scholarly Level |
Faculty; Graduate
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Rights URI | |
Aggregated Source Repository |
DSpace
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Rights
Attribution-NonCommercial-NoDerivatives 4.0 International