Spatially Resolved Ion Density Measurements in an Oxyfuel Cutting Flame

Martin, Christopher R.; Untăroiu, Alexandrina; Xu, Kemu

doi:10.1080/00102202.2020.1792458

Cited by 7 publications

(4 citation statements)

References 23 publications

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“…As can be seen from Fig. 8, the maximum magnitude of species number density is 10 18 ∕𝑚3, and this tones with the physical measurement [26]. The sheaths' saturation can be observed by constraining the torch and work surface number densities boundary condition to zero (Section 2.2).…”

Section: Number Densitysupporting

confidence: 70%

“…For this purpose, we consider one section of the preheat fuel outlet i.e., one torch outlet and calculate the area of that section. The torch outlets have a shape close to a triangle [26] and thus the area is found to be 0.51…”

Section: {Table 1}mentioning

confidence: 97%

“…The ions and electrons have a negligible effect on the flow under a low electric potential environment as discussed in Section 2, and both the generation rate of ions and electrons are extracted from the model. The mobility of electrons is 0.2 𝑚 2 𝑉 -1 𝑠 -1 [44] and 0.0018 𝑚 2 𝑉 -1 𝑠 -1 for the ions [26], respectively. Nernst-Einstein relation is used to calculate the molecular diffusivity as follow:…”

Section: Accepted Manuscript N O T C O P Y E D I T E D {Table 4}mentioning

confidence: 99%

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Role of Secondary Ions on the i-v Characteristics of Oxyfuel Flame Subject to an Electric Field

Untăroiu

Rahman

Martin

2023

Journal of Fluids Engineering

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Recent use of ion currents as a sensing strategy in the mechanized oxyfuel cutting process motivated a series of studies which revealed that the steel work piece contributes secondary ions in addition to the primary ions classically identified in the oxyfuel flame. In this work, we present a computational model that has linked carbon related chemi-ions as a source of secondary ions in preheating stage of oxyfuel cutting process subject to electric bias voltages. The flames' response to the electric field at different positive and negative polarity manifested a better understanding of the physical behavior of current- voltage (i-v) relationship. While copper surface exhibits stable and repeatable i-v characteristics, sporadically enhanced current was observed in positive saturation regime for steel surface, and this is believed be due to the presence of secondary chemi-ions. To this extent, a source term of gaseous carbon has been assigned to mimic the 'work surface' reactions. The hypothesis is that since carbon is an important element, it will be diffusing out of the steel surface and evaporating into the flame.

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Section: Number Densitysupporting

confidence: 70%

Section: {Table 1}mentioning

confidence: 97%

Section: Accepted Manuscript N O T C O P Y E D I T E D {Table 4}mentioning

confidence: 99%

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Role of Secondary Ions on the i-v Characteristics of Oxyfuel Flame Subject to an Electric Field

Untăroiu

Rahman

Martin

2023

Journal of Fluids Engineering

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“…Oxyfuel flame temperatures are on the order of 3000K or higher, and ion densities in the outer cone of the flame have been measured to be on the order 10 17 m −3 [16]. Under these conditions, the Debye length is on the order λ ≈ 10 μm.…”

Section: Reasonable Parameter Valuesmentioning

confidence: 99%

A model for a Langmuir sheath in a stagnating dense plasma with secondary ion formation

Martin,

Untaroiu,

Rahman

2024

Phys. Scr.

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This simplified model provides solutions for the current-voltage characteristics of a sheath in a dense flowing plasma when surface chemistry contributes secondary ions. The problem is motivated by the recent discovery that strong transient signals in industrial ion current sensors are caused by chemical reactions with carbon in the steel being cut or welded by oxyfuel processes. Theone-dimensional model considers a quasi-uniform dense plasma flowing towards and stagnating on an absorbing surface, above which there is a source of secondary ions. Because the secondary ions are formed directly in the plasma sheath, theyhave strong impacts on the current-voltage characteristic. With ionic Reynolds number, R, and integral length scale, α, secondary ion formation rate, Ω, and length scale, β, saturation currents are simply R + βΩ until β ≪ 1, at which point, new electrons cannot escape the sheath, and secondary ions have no effect. Floating potential, φ∞ , scales like exp(φ∞ ) ∝ R −3/4 , and secondary ions havelittle impact unless β^2 Ω > 1. Even then, floating potential is only weakly affected by secondary ion formation. The integral length scale, α, is not found to strongly affect the results.

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Design and characteristic analysis of flame cutting nozzles for ultralarge-thickness steel ingots

Yu,

Liu,

Wang

et al. 2024

Arabian Journal of Chemistry

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Spatially Resolved Ion Density Measurements in an Oxyfuel Cutting Flame

Cited by 7 publications

References 23 publications

Role of Secondary Ions on the i-v Characteristics of Oxyfuel Flame Subject to an Electric Field

Role of Secondary Ions on the i-v Characteristics of Oxyfuel Flame Subject to an Electric Field

A model for a Langmuir sheath in a stagnating dense plasma with secondary ion formation

Design and characteristic analysis of flame cutting nozzles for ultralarge-thickness steel ingots

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