Jet‐to‐jet interactions in atmospheric‐pressure plasma jet arrays for surface processing

Abstract

Atmospheric Pressure Plasma Jet (APPJ) arrays are considered as one of the most promising methods for uniform plasma processing of large uneven surfaces. To improve the downstream uniformity and enhance the surface treatment effects, it is important to reveal the mechanisms of the jet‐to‐jet interactions of plasma plumes in the jet array. In this paper, the electrical, optical, and fluid characteristics of the He and Ar three‐channel one‐dimensional (1D) plasma jet arrays with cross‐field needle‐ring electrode structure are studied and compared. It is found that there are divergences in the outside plumes of the propagation trajectory by the repellency of the plasma bullets and the spatial uniformity of the He and Ar plasma jet arrays can be improved with a lower applied voltage and a higher gas flow rate. The deflection angle of side plumes with respect to the central one of He is larger than that of Ar jet array due to the lighter molecular weight and better discharge synchronization. The experimental results show that Ar jet array is more controllable and stable and is more suitable for the design of the practical, simpler, and cheaper scalable plasma jet arrays.

The effects of the tube diameter on the discharge ignition and the plasma properties of atmospheric‐pressure microplasma confined inside capillary

“…In Figure A, in the case of 4 µm, the tip of the microplasma plume inside the capillary reaches as far as 20 mm away from the exit of the quartz tube. The aspect ratio (length/radius) of the microplasma plume reaches as high as 10 4 , which is much higher than those in regular plasma jets of several mm diameter . In Figure B, when the tube diameter increases from 4 to 100 µm, the length of the microplasma plume increases from 20 to 49 mm initially and then grows slowly after the tube diameter reaches 20 µm.…”

“…The aspect ratio (length/radius) of the microplasma plume reaches as high as 10 4 , which is much higher than those in regular plasma jets of several mm diameter. [4,9] In Figure 3B, when the tube diameter increases from 4 to 100 µm, the length of the microplasma plume increases from 20 to 49 mm initially and then grows slowly after the tube diameter reaches 20 µm. In addition, for a tube diameter less than or equal to 20 µm, corona-like air plasma around the capillary is observed.…”

“…Atmospheric-pressure non-thermal plasma jets have been attracting great interests because of their promising applications in plasma medicine [1][2][3] and material processing. [4][5][6][7][8] Generally speaking, the plasma jets are first ignited inside a dielectric tube, and then propagating along a noble gas column guided by the tube. The plasma jet is generated in an open space, rather than in a narrow space in dielectric barrier discharges (DBD).…”

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

“…The jets are combined into honeycomb [18] or linear [19] structures and share the same gas feed and power supply. However, as reported by some authors [20] the individual jets interact with each other (hydro-dynamically by their gas flows and electrically by their electric charges) thus making hard to ignite all plasma jets in a uniform manner. Also, jets at the array edge commonly exhibit different properties (like jet length, plume deviation from the normal etc.)…”

Inactivation by helium cold atmospheric pressure plasma for Escherichia coli and Staphylococcus aureus

“…At atmospheric or low pressures, nonthermal plasma can be induced and sustained using an electric discharge in a gas, using various methods such as the corona, dielectric barrier discharge, or the gliding arc discharge configurations. The generation of a stable plasma plume is considered as an important feature of cold atmospheric pressure plasma jet (CAPPJ) [7]. Many researchers have been studied the effect of cold atmospheric pressure plasma on the thermally sensitive materials using different plasma jet devices [8][9][10].…”