A collisional-radiative model of iron vapour in a thermal arc plasma

Baeva, M.; Uhrlandt, Dirk; Murphy, Anthony B.

doi:10.1088/1361-6463/aa7090

Cited by 10 publications

(10 citation statements)

References 27 publications

(34 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Therefore, the optical emission spectroscopy methods based on the assumption of LTE become problematic due to deviations from the equilibrium atomic state distribution occurring in the arc fringes. The CR model can be used as a diagnostic tool to interpret emission spectroscopy measurements …”

Section: Resultsmentioning

confidence: 99%

Numerical analysis of chemical reaction processes in different anode attachments of a high‐intensity argon arc

Sun

Wang

Zhu

2019

Contributions to Plasma Physics

View full text Add to dashboard Cite

The attachment mode of arc on anode is closely related to the non‐equilibrium chemical kinetics process of the anode region of arc. In this paper, the detailed chemical reaction mechanisms in the flow‐affected region for both diffuse and constricted argon arc attachments are investigated by means of one‐dimensional discharge coupled with a single‐fluid, two‐temperature model. The collisional‐radiative model is used to examine the chemical reaction processes occurring in the anode region, including the arc centreline and fringe region. The numerical results are validated by comparison with available experimental data. The obtained radial distributions of electron temperature, electron density, excited states densities, ionization, and recombination processes reveal that different mechanisms dominate the diffuse and constricted arc‐anode attachments.

show abstract

Section: Resultsmentioning

confidence: 99%

Numerical analysis of chemical reaction processes in different anode attachments of a high‐intensity argon arc

Sun

Wang

Zhu

2019

Contributions to Plasma Physics

View full text Add to dashboard Cite

show abstract

“…3 Kinetic nonequilibrium in a coupled plasma-electrodes arc simulation: (left) distributions of heavyspecies temperature and degree of thermal nonequilibrium given by the ratio T e /T h ; (right) chemical nonequilibrium quantified by distributions of the ratios of the actual number densities of electrons n e and argon ions n Ar+ with respect to those obtained using Saha equations (n e | eq and n Ar+ | eq ) largely impractical due the large computational cost implied. However, de-coupled models can be very useful, for example, to assess the extent in which LTE is satisfied, as exemplified by the work of Baeva et al [8] for the analysis of the effect of iron vapor in a transferred arc.…”

Section: Radiative Nonequilibriummentioning

confidence: 99%

Nonequilibrium Phenomena in (Quasi-)thermal Plasma Flows

Trelles

2019

Plasma Chem Plasma Process

View full text Add to dashboard Cite

Thermal plasmas are utilized in diverse applications that require high power densities or throughputs, such as metal cutting, welding, spraying, metallurgy, and materials synthesis. Thermal plasma applications involve interactions between the highly energetic plasma and working gas streams, confining devices, or processing materials. Whereas thermal plasma implies a state of equilibrium (i.e. Local Thermodynamic Equilibrium, LTE), due to the above interactions, thermal plasma flows depict nonequilibrium phenomena of two types: kinetic and dissipative. Kinetic nonequilibrium manifests microscopically and is caused by localized imbalances between particles and fields interactions. Its occurrence is evidenced, for example, as deviations from thermal equilibrium between heavy-species and electrons or from mass-action laws. In contrast, dissipative nonequilibrium reveals macroscopically and is produced by external driving forces that incite distributed responses, such as the growth of instabilities, the occurrence of self-organization, or the establishment of turbulence. Although kinetic nonequilibrium has been increasingly incorporated in thermal plasma flow models (e.g. finite-rate chemistry, two-temperature models), it is the great advances in numerical computing that is enabling the exploration of dissipative nonequilibrium (e.g. pattern formation, small-scale turbulent features). Both types of nonequilibrium are reviewed, including their estimation and incidence, within the context of computational models and their relevance to thermal plasma sources and processes.

show abstract

“…In the plasma arc, not only iron and iron oxide can be released from the iron ore and liquid bath but also carbon is released from graphite electrode. The amount of iron, iron oxide and carbon vapor depends on the process parameters [35]. Bohr's model is used to describe the structure of hydrogen energy levels [32].…”

Section: Thermodynamic Properties Of Thermal Plasmamentioning

confidence: 99%

Thermodynamic of Liquid Iron Ore Reduction by Hydrogen Thermal Plasma

Seftejani

Schenk

2018

Metals

View full text Add to dashboard Cite

The production of iron using hydrogen as a reducing agent is an alternative to conventional iron- and steel-making processes, with an associated decrease in CO2 emissions. Hydrogen plasma smelting reduction (HPSR) of iron ore is the process of using hydrogen in a plasma state to reduce iron oxides. A hydrogen plasma arc is generated between a hollow graphite electrode and liquid iron oxide. In the present study, the thermodynamics of hydrogen thermal plasma and the reduction of iron oxide using hydrogen at plasma temperatures were studied. Thermodynamics calculations show that hydrogen at high temperatures is atomized, ionized, or excited. The Gibbs free energy changes of iron oxide reductions indicate that activated hydrogen particles are stronger reducing agents than molecular hydrogen. Temperature is the main influencing parameter on the atomization and ionization degree of hydrogen particles. Therefore, to increase the hydrogen ionization degree and, consequently, increase of the reduction rate of iron ore particles, the reduction reactions should take place in the plasma arc zone due to the high temperature of the plasma arc in HPSR. Moreover, the solubility of hydrogen in slag and molten metal are studied and the sequence of hematite reduction reactions is presented.

show abstract

A collisional-radiative model of iron vapour in a thermal arc plasma

Cited by 10 publications

References 27 publications

Numerical analysis of chemical reaction processes in different anode attachments of a high‐intensity argon arc

Numerical analysis of chemical reaction processes in different anode attachments of a high‐intensity argon arc

Nonequilibrium Phenomena in (Quasi-)thermal Plasma Flows

Thermodynamic of Liquid Iron Ore Reduction by Hydrogen Thermal Plasma

Contact Info

Product

Resources

About