Influence of discharge and jet flow coupling on atmospheric pressure plasma homogeneity

Nizard, Harry; Gaudy, T; Toutant, Adrien; Iacono, J.; Descamps, P.; Leempoel, P.; Massines, Françoise

doi:10.1088/0022-3727/48/41/415204

Cited by 12 publications

(10 citation statements)

References 20 publications

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“…The high gas temperature of the RF-APGD plasmas is also not desired for the treatment of the heat-sensitive materials, especially for the living biomaterials. In previous studies, control of the local environment with the aid of the solid or gas shielding or with the enclosure of the plasma generator inside a chamber filled with a specific gas was one of the popular methods to increase the volume of the cold plasma jet [19][20][21][22][23][24]. And the shielding effects using gas or solid cylinder have also been used to modulate the length or volume of the RF-driven CAP jets [25][26][27][28][29].…”

Section: Introductionmentioning

confidence: 99%

Characteristics of a radio-frequency cold atmospheric plasma jet produced with a hybrid cross-linear-field electrode configuration

Khan

et al. 2019

Plasma Sci. Technol.

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Cold atmospheric plasma (CAP) jet has wide applications in various fields including advanced materials synthesis and modifications, biomedicine, environmental protection and energy saving, etc. Appropriate control on the volume, temperature and chemically reactive species concentrations of the CAP jet is of great importance in actual applications. In this paper, an radio-frequency atmospheric-pressure glow discharge (RF-APGD) plasma generator with a hybrid cross-linear-field electrode configuration is proposed. The experimental results show that, with the aid of the copper mesh located at the downstream of the traditional co-axial-type plasma generator with a cross-field electrode configuration, a linear field between the inner powered electrode of the traditional plasma generator and the copper mesh can be established. This linerfield can, to some extent, enhance the discharges at the upstream of the copper mesh, resulting in small increments (all less than 12.5%) of the species emission intensities, electron excitation temperatures and gas temperatures by keeping other parameters being unchanged. And due to the intrinsic transparent and conducting features of the grounded copper mesh to the gas flowing, electric current and heat flux of the plasma plumes, a plasma region with higher concentrations of chemically reactive species and larger plasma plume diameters is obtained at the downstream of the grounded copper mesh on the same level of the gas temperature and electron excitation temperature compared to those of the plasma free jet. In addition, the charged particle number densities at the same downstream axial location of the grounded copper mesh decrease significantly compared to those of the plasma free jet. This means that the copper mesh is also, to some extent, helpful for separating the chemically reactive neutral species from the charged particles inside a plasma environment. The preceding results indicate that the cross-linear-field electrode configuration of the plasma generator is an effective approach for tuning the characteristics of the RF-APGD plasma jet in order to obtain an appropriate combination of the plasma jet properties with higher chemically reactive species concentrations, especially relative higher number densities of neutral species, larger plasma volumes and lower gas temperatures.

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Section: Introductionmentioning

confidence: 99%

Characteristics of a radio-frequency cold atmospheric plasma jet produced with a hybrid cross-linear-field electrode configuration

Khan

et al. 2019

Plasma Sci. Technol.

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“…For the gas discharge plasma sources operating in an open environment, it is one of the most popular methods for the control of the local environment in the plasma jet region by using the solid or gas shielding effect or by enclosing the plasma generator inside a chamber filled with a specific gas atmosphere for either the atmospheric thermal or cold plasmas [33][34][35][36][37][38][39][40][41][42][43]. For the usage of the solid shielding effect, there are two different situations: one is the shielding of the AP-DBDs in a capillary tube in which the discharge current passes through the whole space inside the tube [44][45][46][47][48][49][50][51][52], while another is the shielding for the post-discharge region, e.g., the RF-CAP jet in this study, where no discharges occur, and consequently, no discharge currents exist in the shielding tube [35,37,41].…”

Section: Introductionmentioning

confidence: 99%

Influences of the inner diameter of the solid shielding tube on the characteristics of the radio-frequency cold atmospheric plasma jet

Khan

2019

Plasma Sci. Technol.

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Active control of the local environment of the cold atmospheric plasma (CAP) jet is of great importance in actual applications since the CAP operates in an open atmosphere with the inevitable entrainment of the surrounding cold air. In this paper, the solid shielding effects of the cylindrical quartz tubes with different inner diameters on the characteristics of the CAP jets driven by a radio-frequency (RF) power supply are studied experimentally. The experimental results show that the total length of the shielded plasma jet can be increased significantly by an appropriate combination of the quartz tube inner diameter and that of the plasma generator nozzle exit with other parameters being unchanged. This phenomenon may be qualitatively attributed to the loss of diffusion of the charged particles in the radial direction under different inner diameters of the quartz tubes. Compared with the plasma free jet, the plasma shielding jet is produced with optimized parameters including longer plasma jet length, higher concentrations of chemically reactive species, higher rotational, vibrational, and electron excitation temperatures when the inner diameters of the solid shielding tube and the generator nozzle exit are the same. A maximum plasma jet length of 52.0 cm is obtained in contrast to that of 5.0 cm of the plasma free jet in this study. The experimental results indicate that the solid shielding effect provides a new method for the active control of the local environment of the RF-CAP jet operating in an open atmosphere.Keywords: cold atmospheric plasma jet, radio-frequency glow discharge, solid shielding effect, effect of the tube inner diameter, active control of plasma jet characteristics

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“…from jets in the central area so that the treatment uniformity is compromised. Another method to obtain a large area plasma plume at atmospheric pressure relies on cooperative merging of two or more individual jets into a wide plasma column (up to 2-cm-diam) as reported in [21,22]. However, the jets merging works properly only within a limited range of gas flows and applied voltages and with He as working gas, which is not feasible for surface processing applications.…”

Section: Introductionmentioning

confidence: 99%

Uniform surface modification of polyethylene terephthalate (PET) by atmospheric pressure plasma jet with a horn-like nozzle

Mui

Mota

Quade

et al. 2018

Surface and Coatings Technology

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This work reports on surface modification of polyethylene terephthalate (PET) polymer by an atmospheric pressure plasma jet (APPJ) operated with argon. A distinguishable feature of this device is that it terminates with a conical horn-like nozzle. Three different nozzles diameters were employed with the purpose to obtain uniform surface modification over large area. Treatments in small 3D objects that fit inside the conical horn were also conducted. In this study, water contact angle (WCA) measurements and X-ray photoelectron spectroscopy (XPS) were performed to assess the samples wettability and the surface elemental composition, as well as, their radial distribution. Plasma-induced changes on the polymer surface morphology were evaluated by Atomic Force Microscopy (AFM). Electrical characterization of the plasma and investigation of the effect of the gas flow rate on the discharge power were carried out. After the plasma treatment PET surface became more hydrophilic over the entire area covered by the nozzle. This effect is caused by the incorporation of oxygen containing polar groups on the surface. It was also observed that depending on process parameters, the plasma treatment can extend even outside the area of the conical horn. The degree of surface modification depends on plasma dose while the treatment uniformity is determined mostly by the distance to the sample. Overall, a quite uniform surface modification was obtained over the entire area covered by the jet nozzle. Thus, the results suggest that by simply changing the jet geometry and choosing the right treatment parameters one can achieve a uniform treatment over an area whose size is determined by the horn diameter.

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Influence of discharge and jet flow coupling on atmospheric pressure plasma homogeneity

Cited by 12 publications

References 20 publications

Characteristics of a radio-frequency cold atmospheric plasma jet produced with a hybrid cross-linear-field electrode configuration

Characteristics of a radio-frequency cold atmospheric plasma jet produced with a hybrid cross-linear-field electrode configuration

Influences of the inner diameter of the solid shielding tube on the characteristics of the radio-frequency cold atmospheric plasma jet

Uniform surface modification of polyethylene terephthalate (PET) by atmospheric pressure plasma jet with a horn-like nozzle

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