Modeling of the production of ultra fine Aluminium particles in rapid quenching turbulent flow

Aristizabal, Felipe; Munz, R. J.; Berk, Dimitrios

doi:10.1016/j.jaerosci.2005.04.001

Cited by 15 publications

(10 citation statements)

References 35 publications

(51 reference statements)

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“…This is especially true in the early stages of the nanoparticle formation and growth processes [2]. Computational fluid dynamics (CFD) has been developed for many years and a variety of numerical techniques have been developed and utilized for studying particle dynamics [3][4][5][6][7][8][9][10]. CFD has enabled engineers to achieve their goals more rapidly and cost effectively [11].…”

Section: Introductionmentioning

confidence: 99%

Growth Mechanisms of Nanostructured Titania in Turbulent Reacting Flows

Garrick

2015

Journal of Nanotechnology

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Titanium dioxide (titania) is used in chemical sensors, pigments, and paints and holds promise as an antimicrobial agent. This is due to its photoinduced activity and, in nanostructured form, its high specific surface area. Particle size and surface area result from the interplay of fluid, chemical, and thermal dynamics as well as nucleation, condensation and coagulation. After nucleation, condensation, and coagulation are the dominant phenomena affecting the particle size distribution. Manufacture of nanostructured titania via gas-phase synthesis often occurs under turbulent flow conditions. This study examines the competition between coagulation and condensation in the growth of nanostructured titania. Direct numerical simulation is utilized in simulating the hydrolysis of titanium tetrachloride to produce titania in a turbulent, planar jet. The fluid, chemical, and particle fields are resolved as a function of space and time. As a result, knowledge of titania is available as a function of space, time, and phase (vapor or particle), facilitating the analysis of the particle dynamics by mechanism. Results show that in the proximal region of the jet nucleation and condensation are the dominant mechanisms. However once the jet potential core collapses and turbulent mixing begins, coagulation is the dominant mechanism. The data also shows that the coagulation growth-rate is as much as twice the condensation growth-rate.

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Section: Introductionmentioning

confidence: 99%

Growth Mechanisms of Nanostructured Titania in Turbulent Reacting Flows

Garrick

2015

Journal of Nanotechnology

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“…Particularly, models based on aerosol dynamics have been used to study nanopowder production using several types of thermal plasmas, as described in an earlier review article [12]. By virtue of the efforts of several groups, the spatial distributions of nanopowder around plasmas or in downstream chambers have been clarified while taking account of both growth and transport under various conditions [22][23][24][25][26][27][28][29][30][31][32][33]. However, all those simulations were restricted in the steady fields of the nanopowder as well as the plasma flow.…”

Section: Thermal Plasma For Nanopowder Productionmentioning

confidence: 99%

“…z and r denote the axial and radial positions, respectively. Based on the measurement results [96], the radial profiles of the axial velocity u nozzle and temperature T nozzle at the nozzle exit are given as the following polynomials: (26) as shown in Fig. 2.…”

Section: Computational Conditions a Two-dimensionalmentioning

confidence: 99%

Modeling and simulation of a turbulent‐like thermal plasma jet for nanopowder production

Shigeta

2018

IEEJ Transactions Elec Engng

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This paper discusses theoretical models and numerical methods to simulate turbulent thermal plasma flow transporting a nanopowder. In addition to a thermal plasma flow model, a sophisticated model is described mathematically for the nanopowder's collective growth by homogeneous nucleation, heterogeneous condensation, and coagulation among nanoparticles, and also transport by convection, diffusion, and thermophoresis, simultaneously. Demonstrative simulations show clearly that a suitable numerical method with high‐order accuracy should be used for long and robust simulation capturing multiscale eddies and steep gradients of temperature, which are the turbulent features of thermal plasma flows with locally variable density, transport properties and Mach numbers. Eddies are first generated at the interfacial region between the plasma jet and ambient nonionized gas by fluid‐dynamic instability. As a result of the eddies' generation–breakup process, the plasma flow entrains the ambient cold gas and deforms its shape traveling downstream. Numerous sub‐nanometer particles are generated by nucleation and condensation in the thin layers near the plasma jet. Those particles diffuse and increase their size, thus decreasing their number by coagulation. Cross‐correlation analysis suggests that the nanopowder distribution distant from a plasma jet can be controlled by controlling the temperature fluctuation at the upstream plasma fringe. © 2018 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

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“…Particularly, mathematically described models based on aerosol dynamics have been adopted to elucidate nanopowder fabrication using thermal plasmas of several types [13]. Because of the efforts of several groups, the spatial distributions of nanopowder around plasmas or in downstream chambers have been revealed while considering both growth and transport in various conditions [27][28][29][30][31][32][33][34][35][36][37][38]. However, all of those simulations were restricted in steady fields of the nanopowder as well as the plasma flow.…”

Section: Introductionmentioning

confidence: 99%

Simulating Turbulent Thermal Plasma Flows for Nanopowder Fabrication

Shigeta

2020

Plasma Chem Plasma Process

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This article presents descriptions of theoretical models and numerical methods for simulating turbulent thermal plasma flow with nanopowder growth. Turbulence models must express turbulent and laminar states because both states co-exist with thermal plasmas showing large density variation and transport properties. Time-dependent 3D simulations are conducted based on Large Eddy Simulation using a dynamic Smagorinsky model. Results show significant difference depending on temporal and spatial discretization schemes and velocity-pressure coupling algorithms. Simulation results demonstrate that advanced numerical methods with high-order accuracy should be used for long and robust computations capturing steep gradients of nanopowder concentration and plasma temperature and 3D dynamic motions of multiscale vortices, which are turbulent features of thermal plasma flows with low Mach numbers. A thermal plasma jet generates a doublelayer structure of inner high-temperature thick vortex rings and outer low-temperature thin vortex rings near the nozzle exit. Flowing downstream, these vortices interact, deform, and break up. Consequently, plasma transits to a complex thermal flow. The widely spreading distribution of multiscale vortices agrees with experimental observations, which are not simulated using conventional methods. Nanopowder is generated from material vapour by nucleation and condensation at interfacial regions between plasma and cold gas. Those regions include numerous vortices. Therefore, the vortices convey the nanopowder, producing a complex distribution of nanopowder. Simultaneously, the nanopowder diffuses and increases in size, decreasing in number by interparticle coagulation. Cross-correlation analysis suggests that a nanopowder distribution distant from a plasma jet can be controlled through temperature fluctuation control at the upstream plasma fringe.

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Modeling of the production of ultra fine Aluminium particles in rapid quenching turbulent flow

Cited by 15 publications

References 35 publications

Growth Mechanisms of Nanostructured Titania in Turbulent Reacting Flows

Growth Mechanisms of Nanostructured Titania in Turbulent Reacting Flows

Modeling and simulation of a turbulent‐like thermal plasma jet for nanopowder production

Simulating Turbulent Thermal Plasma Flows for Nanopowder Fabrication

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