Probing instabilities in arc plasma devices using binary gas mixtures

Ghorui, S.; Vyšohlíd, Martin; Heberlein, J.; Pfender, E.

doi:10.1103/physreve.76.016404

Cited by 34 publications

(35 citation statements)

References 28 publications

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“…Similar results have been obtained also by Chen for a different ICP torch configuration [28] and the accumulation of hydrogen in the cold boundary layer of a thermal spray torch was simulated by Ghorui et al [43] using a two-temperature combined diffusion approach. These results are in agreement also with previous investigations by Murphy [42] in which a peak of hydrogen mass fraction has been predicted in the low-temperature fringes of a free burning arc.…”

Section: Mass Fraction Fields and Demixing Effectssupporting

confidence: 72%

A three-dimensional investigation of the effects of excitation frequency and sheath gas mixing in an atmospheric-pressure inductively coupled plasma system

Colombo¹,

Ghedini²,

Sanibondi³

2010

J. Phys. D: Appl. Phys.

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To cite this version:V Colombo, E Ghedini, P Sanibondi. A three-dimensional investigation of the effects of excitation frequency and sheath gas mixing in an atmospheric-pressure inductively coupled plasma system. Journal of Physics D: Applied Physics, IOP Publishing, 2010, 43 (10), pp.105202. <10.1088/0022-3727/43/10/105202>. A three-dimensional investigation of the effects of excitation frequency and sheath gas mixing in an atmospheric-pressure inductively-coupled plasma system V Colombo, E Ghedini, P Sanibondi Dipartimento di Ingegneria delle Costruzioni Meccaniche, Nucleari, Aeronautiche e di Metallurgia (DIEM), Alma Mater Studiorum -Università di Bologna, Via Saragozza 8, 40123 Bologna, Italy E-mail: paolo.sanibondi@unibo.it Abstract.A three dimensional numerical model for the simulation of the behavior of a commercial inductively coupled plasma (ICP) torch with non-axisymmetric reaction chamber has been developed, taking in account turbulence and gas mixing through RNG k-theory and the combined diffusion approach of Murphy, respectively.The effects of changing coil current frequency, the hydrogen mixing in an argon primary gas and the flow patterns and temperature distributions which take place in a reaction chamber with a lateral gas outlet system and two observation windows have been investigated, with the final aim of setting up a computational tool able to predict the main features of plasma assisted treating and processing of injected raw materials.Three-dimensional shapes of the temperature, velocity and mass fraction fields have been obtained and analyzed for an Ar-H 2 mixture at atmospheric pressure.Computations have been performed with two different coil current frequencies, i.e. 3 MHz and 13.56 MHz, showing that for the lower value the 3-D effects in the discharge are enhanced.Accurate mixing and demixing mechanisms have been investigated in both cases, including considerations on the relative importance of different thermal diffusion contributions due to mole fraction and temperature gradients.Temperature distributions in the reaction chamber for different cases have been correlated to different flow patterns and recirculation flows which take place as a consequence of the non-axisymmetry of the reaction chamber.

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Section: Mass Fraction Fields and Demixing Effectssupporting

confidence: 72%

A three-dimensional investigation of the effects of excitation frequency and sheath gas mixing in an atmospheric-pressure inductively coupled plasma system

Colombo¹,

Ghedini²,

Sanibondi³

2010

J. Phys. D: Appl. Phys.

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“…The most common type could be that caused by the length change of the arc column between the cathode tip and the anode, due to the arc root movement on the anode surface owing to the interaction between the drag force of gas flow and the electro-magnetic force around the arc column. Many factors could affect the attachment pattern and the form of movement of the arc root on the anode surface, such as the working gas component, feeding method, flow rate, arc current and boundary layer between the anode surface and the arc column [6,7,9]. The amplitude and frequency of the fluctuation change in a wide range and can be over 100% of its average voltage and several kilohertz [7,8,10].…”

Section: Introductionmentioning

confidence: 99%

“…Many factors could affect the attachment pattern and the form of movement of the arc root on the anode surface, such as the working gas component, feeding method, flow rate, arc current and boundary layer between the anode surface and the arc column [6,7,9]. The amplitude and frequency of the fluctuation change in a wide range and can be over 100% of its average voltage and several kilohertz [7,8,10]. Another type of arc voltage fluctuation is considered originating from the power supply.…”

Section: Introductionmentioning

confidence: 99%

Fluctuation characteristics of arc voltage and jet flow in a non-transferred dc plasma generated at reduced pressure

Pan¹,

Guo

Meng

et al. 2009

Plasma Sources Sci. Technol.

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A torch with a set of inter-electrode inserts between the cathode and the anode/nozzle with a wide nozzle exit was designed to generate plasma jets at chamber pressures of 500-10 000 Pa. The variation of the arc voltage was examined with the change in working parameters such as gas flow rate and chamber pressure. The fluctuation in the arc voltage was recorded with an oscilloscope, and the plasma jet fluctuation near the torch exit was observed with a high-speed video camera and detected with a double-electrostatic probe. Results show that the 300 Hz wave originated from the tri-phase rectified power supply was always detected under all generating conditions. Helmholtz oscillations over 3000 Hz was detected superposed on the 300 Hz wave at gas flow rates higher than 8.8 slm with a peak to valley amplitude lower than 5% of the average voltage value. No appreciable voltage fluctuation caused by the irregular arc root movement is detected, and mechanisms for the arc voltage and jet flow fluctuations are discussed.

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“…For the ions, D s is the ambipolar diffusion coefficient; for neutral species, D s is the effective diffusion coefficient of species s calculated from the binary diffusion coefficients according to the first‐order Chapman–Enskog approximation . The effective binary diffusion approximation has been recently used in studying plasma instabilities in a dc plasma torch and in the simulation of argon free‐burning arc …”

Section: Description Of the Modelmentioning

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

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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.

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Probing instabilities in arc plasma devices using binary gas mixtures

Cited by 34 publications

References 28 publications

A three-dimensional investigation of the effects of excitation frequency and sheath gas mixing in an atmospheric-pressure inductively coupled plasma system

A three-dimensional investigation of the effects of excitation frequency and sheath gas mixing in an atmospheric-pressure inductively coupled plasma system

Fluctuation characteristics of arc voltage and jet flow in a non-transferred dc plasma generated at reduced pressure

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

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