Production of nanometer-sized metal oxide particles by gas phase reaction in a free jet. II: Particle size and neck formation - comparison with theory with theory

Robert Windeler, Kari Lehtinen, Sheldon Friedlander

Research output: Contribution to journalArticleScientificpeer-review

40 Citations (Scopus)

Abstract

Experimental measurements of nanosized primary particle diameters were compared with calculated values based on a collision-coalescence model.
The method of analysis permits calculation of the primary particle size when growth is collision limited (individual particles colliding), coalescence limited (primary particles coalescing in agglomerates), or in a transition regime (particles coalescing about as fast as they collide).
Calculated particle sizes compared well with experimental measurements. Particle characteristics were studied along the jet axis for the following conditions: exit velocity = 27.8 m/s, volume loading = 3.2 × 10−7, flame gas flow rate = 33 1/min.
The growth of niobium oxide particles (largest diffusion coefficient) was collision limited, yielding particles that are large and nonagglomerated. The growth of titania particles (mid-range diffusion coefficient) occurred in the collision limited and coalescence limited regimes to form mid-sized particles in agglomerates.
The growth of alumina particles (lowest diffusion coefficient) was coalescence limited forming small, oblong particles necked together in large agglomerates. The extent of necking between particles can be estimated from the collision and coalescence times along the jet axis.
When the coalescence time rapidly exceeds the collision time, subsequent collisions form agglomerates which are loosely held together.
When the coalescence time slowly becomes longer than the collision time, strong necks form between the particles.
Original languageEnglish
Pages (from-to)191-205
JournalAerosol Science and Technology
Volume27
Issue number2
DOIs
Publication statusPublished - 1997
MoE publication typeA1 Journal article-refereed

Fingerprint

free jet
gas phase reaction
Coalescence
Oxides
Particles (particulate matter)
Gases
Metals
Particle size
particle size
coalescence
collision
Niobium oxide
Aluminum Oxide
particle
comparison
metal oxide
Flow of gases
Alumina
Titanium
Flow rate

Cite this

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title = "Production of nanometer-sized metal oxide particles by gas phase reaction in a free jet. II: Particle size and neck formation - comparison with theory with theory",
abstract = "Experimental measurements of nanosized primary particle diameters were compared with calculated values based on a collision-coalescence model. The method of analysis permits calculation of the primary particle size when growth is collision limited (individual particles colliding), coalescence limited (primary particles coalescing in agglomerates), or in a transition regime (particles coalescing about as fast as they collide). Calculated particle sizes compared well with experimental measurements. Particle characteristics were studied along the jet axis for the following conditions: exit velocity = 27.8 m/s, volume loading = 3.2 × 10−7, flame gas flow rate = 33 1/min. The growth of niobium oxide particles (largest diffusion coefficient) was collision limited, yielding particles that are large and nonagglomerated. The growth of titania particles (mid-range diffusion coefficient) occurred in the collision limited and coalescence limited regimes to form mid-sized particles in agglomerates. The growth of alumina particles (lowest diffusion coefficient) was coalescence limited forming small, oblong particles necked together in large agglomerates. The extent of necking between particles can be estimated from the collision and coalescence times along the jet axis. When the coalescence time rapidly exceeds the collision time, subsequent collisions form agglomerates which are loosely held together. When the coalescence time slowly becomes longer than the collision time, strong necks form between the particles.",
author = "Robert Windeler and Kari Lehtinen and Sheldon Friedlander",
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language = "English",
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pages = "191--205",
journal = "Aerosol Science and Technology",
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}

Production of nanometer-sized metal oxide particles by gas phase reaction in a free jet. II : Particle size and neck formation - comparison with theory with theory. / Windeler, Robert; Lehtinen, Kari; Friedlander, Sheldon.

In: Aerosol Science and Technology, Vol. 27, No. 2, 1997, p. 191-205.

Research output: Contribution to journalArticleScientificpeer-review

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PY - 1997

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N2 - Experimental measurements of nanosized primary particle diameters were compared with calculated values based on a collision-coalescence model. The method of analysis permits calculation of the primary particle size when growth is collision limited (individual particles colliding), coalescence limited (primary particles coalescing in agglomerates), or in a transition regime (particles coalescing about as fast as they collide). Calculated particle sizes compared well with experimental measurements. Particle characteristics were studied along the jet axis for the following conditions: exit velocity = 27.8 m/s, volume loading = 3.2 × 10−7, flame gas flow rate = 33 1/min. The growth of niobium oxide particles (largest diffusion coefficient) was collision limited, yielding particles that are large and nonagglomerated. The growth of titania particles (mid-range diffusion coefficient) occurred in the collision limited and coalescence limited regimes to form mid-sized particles in agglomerates. The growth of alumina particles (lowest diffusion coefficient) was coalescence limited forming small, oblong particles necked together in large agglomerates. The extent of necking between particles can be estimated from the collision and coalescence times along the jet axis. When the coalescence time rapidly exceeds the collision time, subsequent collisions form agglomerates which are loosely held together. When the coalescence time slowly becomes longer than the collision time, strong necks form between the particles.

AB - Experimental measurements of nanosized primary particle diameters were compared with calculated values based on a collision-coalescence model. The method of analysis permits calculation of the primary particle size when growth is collision limited (individual particles colliding), coalescence limited (primary particles coalescing in agglomerates), or in a transition regime (particles coalescing about as fast as they collide). Calculated particle sizes compared well with experimental measurements. Particle characteristics were studied along the jet axis for the following conditions: exit velocity = 27.8 m/s, volume loading = 3.2 × 10−7, flame gas flow rate = 33 1/min. The growth of niobium oxide particles (largest diffusion coefficient) was collision limited, yielding particles that are large and nonagglomerated. The growth of titania particles (mid-range diffusion coefficient) occurred in the collision limited and coalescence limited regimes to form mid-sized particles in agglomerates. The growth of alumina particles (lowest diffusion coefficient) was coalescence limited forming small, oblong particles necked together in large agglomerates. The extent of necking between particles can be estimated from the collision and coalescence times along the jet axis. When the coalescence time rapidly exceeds the collision time, subsequent collisions form agglomerates which are loosely held together. When the coalescence time slowly becomes longer than the collision time, strong necks form between the particles.

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