Predicted Anode Arc Attachment by LTE (Local Thermodynamic Equilibrium) and 2-T (Two-Temperature) Arc Models in a Cascaded-Anode DC Plasma Spray Torch

Zhukovskii, Rodion; Chazelas, Christophe; Rat, Vincent; Vardelle, Armelle; Molz, Ron

doi:10.1007/s11666-021-01253-4

Cited by 13 publications

(12 citation statements)

References 58 publications

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“…Several commercial versions for research and industrial purposes are used today (16)(17)(18)(19). The addition of cathodes properly arranged is aimed at mitigating the impact of electrode erosion by reducing the arc current of each cathode while maintaining high electrical power.…”

Section: Current Non-transferred Plasma Torches 21 Energetic Featuresmentioning

confidence: 99%

Relationships between arc plasma jet properties and plasma/liquid interaction mechanisms for the deposition of nanostructured ceramic coatings

Rat¹,

Bienia²,

Dhamale³

et al. 2022

Plasma Phys. Control. Fusion

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Ceramic nanostructured coatings with intermediate thicknesses between 10 and 100 µm exhibit improved thermal and mechanical properties for thermal barrier coatings or wear resistant coatings. Such coatings comply with the technical requirements of aeronautical and automotive applications. This implies to develop deposition processes with high throughput and deposition rates promoting the formation of nanostructured coatings. The use of a liquid phase as a carrier medium of nanoparticles or of solution precursors has been shown to be of major interest when being injected within a thermal plasma jet. The as-sprayed materials can form ceramic nanostructured coatings provided the liquid injection encompassing the physicochemical properties of liquid and its injection method copes with the plasma properties. Especially the repeatability of the interaction phenomena between the liquid phase and the arc jet has a key role in the efficiency deposition so that some research efforts are devoted to stabilize the arc while a liquid jet is continuously injected within the plasma. Alternatively a pulsed arc plasma jet can be generated and associated with a time-phased injection of droplets. This paper presents the different issues related to the arc plasma properties produced by direct plasma torches including the arc instabilities and their influence on plasma/liquid interaction mechanisms leading to the formation of nanomaterials. A focus is made on pulsed plasma spraying associated with a synchronized injection of microsized droplets by means of an inkjet printing method.

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Section: Current Non-transferred Plasma Torches 21 Energetic Featuresmentioning

confidence: 99%

Relationships between arc plasma jet properties and plasma/liquid interaction mechanisms for the deposition of nanostructured ceramic coatings

Rat¹,

Bienia²,

Dhamale³

et al. 2022

Plasma Phys. Control. Fusion

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“…The electrode heating by the electric current is implemented as described in Zhukovskii et al (2021). For that purpose, the heavy species enthalpy field is coupled with the enthalpy of the electrode by the continuity of corresponding temperatures.…”

Section: Electrodes Inclusion In the Computational Domainmentioning

confidence: 99%

Model of a non-transferred arc cascaded-anode plasma torch: the two-temperature formulation

Zhukovskii

Chazelas

Rat

et al. 2021

J. Phys. D: Appl. Phys.

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This study presents an analysis of a three-dimensional unsteady two-temperature simulation of atmospheric pressure direct current electric arc inside a commercial cascaded-anode plasma spray torch; it coupled the arc model with the torch electrodes and used an open-source computational fluid dynamics software (code_saturne). The previously published models of plasma spray torch either deal with conventional plasma torches or assume local thermodynamic equilibrium in cascaded-anode plasma torches. The paper presents the computation of the two-temperature argon plasma properties, compares two enthalpy formulations that differ in association of the ionization part of enthalpy and finally demonstrates the influence of the radiation heat loss data by comparingthe results for two different literature sources. It is the first to compare different enthalpy formulations in the context of plasma torch and discuss the differences in terms of the enthalpy gains and losses. It also explains why an unphysical simulation artifact of electron temperature lower than the heavy species temperature can occur in simulated plasma flow. The solution, then, consists in associating the ionization part of enthalpy to electrons and selecting the appropriate source of the data of radiation heat loss. However, negligible thermal non-equilibrium persists even in the hot core of electric arc, which ensures that the heavy species are heated up by collisions with electrons. The flexibility of the open-source software allows all the necessary modifications and adjustments to achieve satisfactory simulation results. Thus, the paper could be considered as a manual for development of a plasma spray torch model.

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“…Comparing different structures of plasma torch in the same operating condition, less erosion of electrodes is found at high arc voltage and low arc current [28]. Furthermore, the location of anode erosion mainly depends on the heat flux brought by the arc and the region where the arc attachment happens on the anode wall [29]. Apart from a long working lifetime, a proper plasma torch should also have high thermal efficiency for less energy depletion [28,30].…”

Section: Introductionmentioning

confidence: 99%

Numerical analysis of direct-current (DC) plasma processing for high efficient steel surface modification

Wei¹,

Xu²,

Bennett³

et al. 2022

Preprint

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Nowadays, direct-current (dc) non-transferred arc plasma torch has drawn significant interest from both academia and industry due to the capability to process products in an efficient and convenient way. The core of this technology is to clarify and manipulate the arc behavior at the interior of the torch and produces ideal plasma jets for processing. To solve this problem, a quasi-steady axisymmetric model is built to simulate and compare the arc characteristics in different operating conditions and different nozzle structures. The results uncover distinct aspects of the study on arc characteristics, including the detection of the region of primary arc attachment, the effect of changing operating conditions, and the choking effect caused by torch structure. The thermal efficiency focused on processing substrate is also calculated in this paper. The results show that increasing mass flow rate brings better thermal efficiency, whereas improving the arc current value causes the opposite result. Meanwhile, two types of nozzle are discussed by thermal efficiency, and the wide nozzle is chosen for torch optimization due to its high power efficiency. The secondary arc attachment on the metal substrate is discovered, but its effect on the processing could be ignored for the extremely low electric current value.

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Predicted Anode Arc Attachment by LTE (Local Thermodynamic Equilibrium) and 2-T (Two-Temperature) Arc Models in a Cascaded-Anode DC Plasma Spray Torch

Cited by 13 publications

References 58 publications

Relationships between arc plasma jet properties and plasma/liquid interaction mechanisms for the deposition of nanostructured ceramic coatings

Relationships between arc plasma jet properties and plasma/liquid interaction mechanisms for the deposition of nanostructured ceramic coatings

Model of a non-transferred arc cascaded-anode plasma torch: the two-temperature formulation

Numerical analysis of direct-current (DC) plasma processing for high efficient steel surface modification

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