Numerical simulation of unsteady ArH2 plasma spray impact on a moving substrate

Meillot, E.; Vincent, Stéphane; Bot, Cédric Le; Sarret, F.; Caltagirone, Jean‐Paul; Bianchi, L.

doi:10.1016/j.surfcoat.2014.08.058

Cited by 17 publications

(6 citation statements)

References 25 publications

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“…It's clear that detailed study of impact, spreading and adhesion requires modelling of the associated deformation process. Such processes have been analysed [36][37][38][39][40][41] in some depth, but identifying appropriate input data for the mechanical properties of the material presents a major challenge, particularly since deformation occurs at very high strain rates (as well as high temperatures). For particles that are in some kind of semi-solid state, it's not even clear whether treatments should be based on viscous flow or plasticity models, although in both cases the strain rate (and temperature) dependence need to be taken into account.…”

Section: Fig10mentioning

confidence: 99%

Adhesion of Volcanic Ash Particles under Controlled Conditions and Implications for Their Deposition in Gas Turbines

2015

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A particular (representative) type of ash has been used in this study, having a particle size range of ~10-70 µm. Experimental particle adhesion rate data are considered in conjunction with CFD modeling of particle velocities and temperatures. This ash becomes soft above ~700˚C and it has been confirmed that a sharp increase is observed in the likelihood of adhesion as particle temperatures move into this range. Particle size is important and those in the approximate range 10-30 µm are most likely to adhere. This corresponds fairly closely with the size range that is most likely to enter a combustion chamber and turbine.

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Section: Fig10mentioning

confidence: 99%

Adhesion of Volcanic Ash Particles under Controlled Conditions and Implications for Their Deposition in Gas Turbines

2015

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“…Large Eddy Simulation (LES) approaches have been a recent trend for thermal plasma flow simulations [6,42,[80][81][82][83][84][85][86][87][88][89][90]. LES, a time-dependent approach, treats dynamic motions of large vortices directly on a grid system and models only turbulence composed of small vortices, unresolved by the grid element size.…”

Section: Approximations For Eddy Diffusivitymentioning

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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“…Large eddy simulation (LES) approaches have been a recent trend for thermal plasma flow simulations [6,[72][73][74][75][76][77][78][79][80][81][82]. LES is a time-dependent approach that deals with dynamic motions of large eddies directly using a grid system and models only turbulence composed of small eddies, unresolved by the grid element size.…”

Section: Approximations For Eddy Diffusivity a Turbulentmentioning

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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Numerical simulation of unsteady ArH2 plasma spray impact on a moving substrate

Cited by 17 publications

References 25 publications

Adhesion of Volcanic Ash Particles under Controlled Conditions and Implications for Their Deposition in Gas Turbines

Adhesion of Volcanic Ash Particles under Controlled Conditions and Implications for Their Deposition in Gas Turbines

Simulating Turbulent Thermal Plasma Flows for Nanopowder Fabrication

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

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