Variational multiscale method for nonequilibrium plasma flows

Trelles, Juan Pablo; Modirkhazeni, S. Mahnaz

doi:10.1016/j.cma.2014.09.001

Cited by 44 publications

(78 citation statements)

References 125 publications

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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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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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“…Still the lack of models to accurately simulate the flow in high resolution and to analyze the effects of plasma actuators on boundary layer and wake control is evident. Some interesting studies have been carried out were previously both experimental and numerical until recently . An early numerical study simulating the DBD actuator based on Debye length was carried out.…”

Section: Introductionmentioning

confidence: 99%

“…Their model here is based on the Debye length parameter and on a maximum wall charge density. The effects of a plasma actuator for flow control separation on a blade are also demonstrated numerically.…”

Section: Introductionmentioning

confidence: 99%

“…Some interesting studies have been carried out were previously both experimental and numerical 5,7-10 until recently. [11][12][13][14][15] An early numerical study simulating the DBD actuator 4,16 based on Debye length was carried out. In this model, the charge distribution equation was solved based on the Debye length, and the body forces were calculated from electric field obtained by solving the potential Poisson equation.…”

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confidence: 99%

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A plasma‐fluid model for EHD flow in DBD actuators and experimental validation

Mushyam

Rodrigues

Páscoa

2019

Numerical Methods in Fluids

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Summary A numerical method to simulate plasma induced electrohydrodynamic flow is proposed in this study. The numerical model consists of three components. Firstly, a potential module to simulate temporal potential and electric field generated in the ionized fluid. Secondly, a plasma module to simulate plasma development and charge particle densities. Finally, a fluid module to simulate the flow affected by the body forces induced by the movement of the charged particles. Fluid flow is modeled using modified predictor‐corrector strategy as proposed in the marker and cell method. The velocity field was corrected to achieve incompressible flow by calculating pressure correction factors, considered in all cells. Numerical convergence and time sensitivity analysis were carried to confirm grid independence and determine an efficient time step for simulations. Numerical computations are validated by comparing with experimental results of discharge currents and current densities. They were found to be in very good agreement thus providing an extensive validation. Furthermore, quiescent flow over a dielectric barrier discharge actuator is simulated in the this study, using the proposed plasma‐fluid model, to model flow evolution and resolve temporal flow features for detailed analysis. The streamline and vorticity plots were analyzed and compared with experimental results, and flow results were found to be in‐line with the experiments.

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“… Theoretical and computational studies will be powerful approaches. However, after the experiment by Pfender et al [2] in 1991, there has been no report of successful simulation of a turbulent thermal plasma jet having multi-scale vortices in spite of great efforts by several groups [4] [5] [6] [7]. (Most of their works focused on plasma generation inside the nozzle.)…”

Section: Introductionmentioning

confidence: 99%

Numerical Study of Axial Magnetic Effects on a Turbulent Thermal Plasma Jet for Nanopowder Production Using 3D Time-Dependent Simulation

Shigeta¹

2018

JFCMV

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Abstract3D time-dependent simulations are performed using a computational method suitable for thermal plasma flows to capture a turbulent field induced by a thermal plasma jet and steep gradients in nanopowder distributions. A mathematical model with a simple form is developed to describe effectively simultaneous processes of growth and transport of nanopowder in/around a thermal plasma flow. This growth-transport model obtains the spatial distributions of the number density and mean diameter of nanopowder with a lower computational cost. The results show that an argon thermal plasma jet induces multi-scale vortices even far from itself. A double-layer structure of high-temperature thicker vortex rings surrounded by low-temperature thinner vortex rings is generated in the upstream region. As the vortex rings flow downstream, the high-temperature thicker vortex rings deform largely whereas the low-temperature thinner vortex rings break up into smaller vortices. Nanopowder is generated at the fringe of plasma and transported widely outside the plasma region. The nanopowder grows up collectively by coagulation decreasing particle number as well as homogeneous nucleation and heterogeneous condensation. When a uniform magnetic field is applied in the axial direction, a longer and straighter thermal plasma jet is obtained because of Lorentz force and Joule heating. Larger nanopowder is produced around the plasma because turbulent diffusions of silicon vapor and nanoparticles by vortices are suppressed as well.

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Variational multiscale method for nonequilibrium plasma flows

Cited by 44 publications

References 125 publications

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

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

A plasma‐fluid model for EHD flow in DBD actuators and experimental validation

Numerical Study of Axial Magnetic Effects on a Turbulent Thermal Plasma Jet for Nanopowder Production Using 3D Time-Dependent Simulation

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