Effect of CF<sub>4</sub> concentration on the discharge dynamics and reactive species distribution of atmospheric nanosecond pulsed He plasma jet

Zhao, Huan; Wang, Lijun; Liu, Jie

doi:10.1088/1361-6463/acf6d1

Cited by 3 publications

(1 citation statement)

References 64 publications

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“…Researches shown that the addition of a small amount of O 2 will increase the ionization intensity and electron density in He APPJ and significantly increase the density of atomic fluorine (F) in He/CF 4 plasmas [19,20]. Moreover, it was found in our previous work [21,22] that the ionization rate of He/CF 4 APPJ was enhanced and the density of some RFS increased at a small amount of CF 4 . Therefore, selecting the appropriate O 2 content and studying the effect of O 2 additive on APPJ characteristics and RFS content in the interaction between He/CF 4 APPJ and dielectric surfaces at a small amount of CF 4 have become the focus of this paper.…”

Section: Introductionmentioning

confidence: 87%

Experimental study of the influence of O₂ content on electrical and optical characteristics of He/CF₄ APPJ

Wang,

Zhao,

Liu

et al. 2024

J. Phys. D: Appl. Phys.

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CF4 is an important source of reactive F-containing species (RFS) so that it is used to mix with inert gas as the working gas of atmospheric pressure plasma jet (APPJ) for material surface fluoridation modification. The addition of a small amount of O2 can increase the density of RFS in He/CF4 APPJ. Therefore, the hydrodynamic, electrical and optical properties of He/CF4/O2 APPJ interacting with the dielectric are experimentally investigated in this paper. Meanwhile, the influence of the excitation source on plasma discharge is discussed in detail and the internal mechanism of the experimental phenomenon in this paper is analyzed using the simulation results based on the model established in the previous paper. It is found that the addition of a small amount of O2 can increase the intensity and accelerate the axial propagation speed of He/CF4 APPJ due to the low ionization energy of O2 and the increase of the Penning ionization between metastable He and O2. With the increase of O2 content, the stability of the discharge is gradually enhanced due to the electron attachment reaction of O2 and the position of the primary current pulse in each half voltage cycle gradually approaches the position of the peak voltage because the increase in O2 content raises the breakdown threshold in dielectric barrier discharge (DBD) region. In the presence of downstream dielectric, the addition of 0.1%O2 does not significantly change the radial development radius of APPJ due to the higher electron attachment rate and electron collision excitation loss power. The discharge pulse intensity is generally reduced compared to the absence of dielectric and the glow discharge in the strict sense no longer exists. The continuous spectrum intensity of RFS increases with the addition of a small amount of O2 while decreases significantly when O2 content is too high.

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Section: Introductionmentioning

confidence: 87%

Experimental study of the influence of O₂ content on electrical and optical characteristics of He/CF₄ APPJ

Wang,

Zhao,

Liu

et al. 2024

J. Phys. D: Appl. Phys.

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Influence of O2 content on surface modification of epoxy resin using He/CF4 atmospheric pressure plasma jet to improve surface flashover strength

Wang,

Zhao,

Liu

et al. 2024

Physics of Plasmas

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In order to improve the surface flashover strength of the insulation materials and solve the problem that the relatively high price of CF4 restricts the large-scale application of fluorination modification of CF4 atmospheric pressure plasma jet (APPJ) in the industrial field, He/CF4/O2 APPJ with different O2 content is used to treat epoxy resin (EP) dielectric material. By analyzing the results of scanning electron microscopy, atomic force microscopy, and x-ray photoelectron spectroscopy, the influence of O2 content on the multiple characteristics of EP surface before and after APPJ treatment is studied. Flashover experiment is also carried out on EP surface before and after APPJ treatment. It is found that the addition of 0.1% O2 can increase the mature voltage of the EP surface by about 16.10% compared with untreated EP surface. It is concluded that the improvement of the surface flashover strength with a small amount of O2 (within 0.1%) is influenced by the surface roughness and chemical composition of the dielectric. The deposition effect of APPJ on EP surface is enhanced to increase the surface roughness and reaches the best at 0.1% O2, because the addition of excessive O2 will weaken the APPJ intensity. It is speculated that the creepage distance of the EP surface is increased to inhibit the formation of electron collapse and the content of electronegative fluorine and oxygen on the EP surface is increased under a small amount of O2 addition, resulting in the inhibition of the formation of surface flashover.

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Numerical simulation of He atmospheric pressure plasma jet impinging on the tilted dielectric surface

Wang,

Zhao,

Han

et al. 2024

Journal of Applied Physics

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The target surface to be treated in reality is often not smooth and horizontal and may also be in different tilting angles. The treatment of the tilted dielectric surface by the atmospheric pressure plasma jet (APPJ) undoubtedly increases the complexity of surface modification. Therefore, a two-dimensional fluid model is established to reveal the internal mechanism of the interaction between the He APPJ and the tilted dielectric surface by means of numerical simulation. The distribution of the gas flow in a small angular range (0°, 3°, 5°, 8°, 10°, and 15°) is studied. In addition, the effects of the tilt angle on the jet morphology, discharge dynamic properties, and species distribution of the He APPJ are emphatically discussed. It is found that the jet morphology and parameters are no longer symmetrical under the tilted surface. With the increase in the tilt angle, the enhanced electric field in the upper surface region leads to the increase in the ionization rate and electron density here, and also accelerates the propagation speed of the jet to the dielectric surface in the atmospheric environment. Driven by the electric field force, the jet is closer to the dielectric surface, resulting in a decrease in the thickness of the cathode sheath and an increase in the surface charge density in the area to the right of the central axis. The influence of the gas flow structure leads to the shortening of the jet development distance and a decrease in the jet velocity on the upper surface. N and O also form higher fluxes on the upper surface due to the increase in the electron density.

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Effect of CF₄ concentration on the discharge dynamics and reactive species distribution of atmospheric nanosecond pulsed He plasma jet

Cited by 3 publications

References 64 publications

Experimental study of the influence of O₂ content on electrical and optical characteristics of He/CF₄ APPJ

Experimental study of the influence of O₂ content on electrical and optical characteristics of He/CF₄ APPJ

Influence of O2 content on surface modification of epoxy resin using He/CF4 atmospheric pressure plasma jet to improve surface flashover strength

Numerical simulation of He atmospheric pressure plasma jet impinging on the tilted dielectric surface

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Effect of CF4 concentration on the discharge dynamics and reactive species distribution of atmospheric nanosecond pulsed He plasma jet

Cited by 3 publications

References 64 publications

Experimental study of the influence of O2 content on electrical and optical characteristics of He/CF4 APPJ

Experimental study of the influence of O2 content on electrical and optical characteristics of He/CF4 APPJ

Influence of O2 content on surface modification of epoxy resin using He/CF4 atmospheric pressure plasma jet to improve surface flashover strength

Numerical simulation of He atmospheric pressure plasma jet impinging on the tilted dielectric surface

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Product

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Effect of CF₄ concentration on the discharge dynamics and reactive species distribution of atmospheric nanosecond pulsed He plasma jet

Experimental study of the influence of O₂ content on electrical and optical characteristics of He/CF₄ APPJ

Experimental study of the influence of O₂ content on electrical and optical characteristics of He/CF₄ APPJ