Stability of direct current transfer to thermionic cathodes: II. Numerical simulation

Benilov, M. S.; Faria, M J

doi:10.1088/0022-3727/40/17/014

Cited by 26 publications

(61 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thus, the time‐dependent solver is capable of computing steady states belonging to the section

a_{1} A

of the diffuse mode and to the section CD of the 3D mode with the spot at the edge. This behavior conforms to results of stability analysis: these are the only stable states, as shown analytically and numerically in the framework of the linear stability theory. The existence of hysteresis, suggested by the time‐dependent modeling and seen in Figure , agrees with the linear stability theory and the experiment (e.g., ref …”

Section: Resultssupporting

confidence: 88%

See 1 more Smart Citation

Computing Different Modes on Cathodes of DC Glow and High‐Pressure Arc Discharges: Time‐Dependent Versus Stationary Solvers

Almeida

Benilov

Cunha

et al. 2016

Plasma Processes & Polymers

View full text Add to dashboard Cite

Complex behavior can appear in the modeling of gas discharges even in apparently simple steady‐state situations. Time‐dependent solvers may fail to deliver essential information in such cases. One of such cases considered in this work is the 1D DC discharge. The other case is represented by multiple multidimensional solutions existing in the theory of DC discharges and describing modes of current transfer with different patterns of spots on the cathodes. It is shown that, although some of the solutions, including those describing beautiful self‐organized patterns, can be computed by means of a time‐dependent solver, in most examples results of time‐dependent modeling are at best incomplete. In most examples, numerical stability of the time‐dependent solver was not equivalent to physical stability.

show abstract

“…Thus, the time‐dependent solver is capable of computing steady states belonging to the section

a_{1} A

Section: Resultssupporting

confidence: 88%

“…This behavior conforms to results of stability analysis: these are the only stable states, as shown analytically and numerically in the framework of the linear stability theory. The existence of hysteresis, suggested by the time‐dependent modeling and seen in Figure , agrees with the linear stability theory and the experiment (e.g., ref …”

Section: Resultsmentioning

confidence: 99%

Computing Different Modes on Cathodes of DC Glow and High‐Pressure Arc Discharges: Time‐Dependent Versus Stationary Solvers

Almeida

Benilov

Cunha

et al. 2016

Plasma Processes & Polymers

View full text Add to dashboard Cite

show abstract

“…(12) for operation with molecular gases. It is worth noting that the validity of such a minimum principle for the steady state is a matter of discussion due to the inherent instability of the cathode spot in an axial position, as shown with a more detailed model of the interaction between the cathode and a plasma arc operating at atmospheric pressure [44,45]. Fig.…”

Section: Modelingmentioning

confidence: 99%

Multi-Electrode Plasma Torches: Motivation for Development and Current State-of-the-Art

Marques¹,

Förster²,

Schein³

2009

TOPPJ

View full text Add to dashboard Cite

Multi-electrode plasma torches are becoming increasingly popular in the thermal spray community due to their good stability and high power plasma jet even when operated with inert gases. Currently the models in use feature either three cathodes and a single anode or three individual anodes connecting to a single cathode. The motivation for development of these plasma torches is based on the inherent instability of single anode/single cathode systems which leads to fluctuating plasma jets resulting in inhomogeneous particle heating. The use of multi-electrode systems has expanded into the realm of low pressure plasma spraying and vacuum plasma spraying with promising results, while atmospheric plasma spraying results show improved coating quality compared to conventional systems. Current research focuses on the development of numerical process modeling as well as the application of advanced diagnostics for process analysis, opening up opportunities for improvement and process control.

show abstract

“…Concerning two-temperature models, five main proposals have been made: the models by Coulombe and Meunier [7] and Zhou and Heberlein [8], the model of Hsu and Pfender [9], [10], the model of Benilov et al [11]- [24], and the model by Schmitz and Riemann [25], [26]. Unlike the one-temperature models, all of them consider the electron diffusion to the cathode.…”

Section: Introductionmentioning

confidence: 99%

“…This model gives lookup tables for the current density (10 5 -10 8 A · m −2 ) and the heat flux to the cathode according to the cathode layer voltage drop and the surface temperature of the cathode. These tables are then used to solve the energy equation in the cathode bulk for a given fixed value of the cathode sheath voltage drop [18]- [24].…”

Section: Introductionmentioning

confidence: 99%

Arc/Cathode Interaction Model

Cayla¹,

Freton²,

Gonzalez³

2008

IEEE Trans. Plasma Sci.

View full text Add to dashboard Cite

A 1-D model of the interaction between an electric arc and a solid refractory cathode has been developed. This model is based on the equilibrium of the charged particle fluxes in the cathode layer by considering current density conservation, and balance of energy at the sheath/presheath and at the sheath/cathode surface interfaces forming a closed system of equations. It allows the sheath and presheath to be described and the main physical quantities to be obtained by only using current density as input parameter. The calculations were performed for atmospheric argon discharge and a tungsten refractory cathode. The results obtained, such as the cathode sheath voltage drop and the power flux transmitted to the cathode, are compared with those of the literature, and good agreement is observed. Moreover, our model can be used for a range of current densities (1 × 10 4 -5 × 10 8 A · m −2 ) accurately describing attachment at low current. The heat flux deduced reaches a maximum of 6 × 10 7 W · m −2 at equilibrium between ionic heating and thermionic cooling. The thermionic electron emission current density is dominant for current densities higher than 5 × 10 6 A · m −2 .

show abstract

Stability of direct current transfer to thermionic cathodes: II. Numerical simulation

Cited by 26 publications

References 25 publications

Computing Different Modes on Cathodes of DC Glow and High‐Pressure Arc Discharges: Time‐Dependent Versus Stationary Solvers

Computing Different Modes on Cathodes of DC Glow and High‐Pressure Arc Discharges: Time‐Dependent Versus Stationary Solvers

Multi-Electrode Plasma Torches: Motivation for Development and Current State-of-the-Art

Arc/Cathode Interaction Model

Contact Info

Product

Resources

About