Numerical study of discharge characteristics of an atmospheric pressure plasma jet with a coaxial dual-channel inlet

Abstract

A two-dimensional axisymmetric fluid model was applied to investigate the influence of N2 flow velocity on the discharge characteristics of a He plasma jet with a coaxial dual-channel inlet. Helium working gas flowed in the annular space of a coaxial tube and N2 flowed in a central stainless steel tube powered by a DC voltage. When N2 flow velocity increases from 0 m/s, the jet appears to be stratified, forming the outer side and inner side of the jet, and the electron density on the outside of the jet is much higher than that on the inside. For different N2 flow velocities, the peak densities of He+ and N2(c3π) appear in the jet head, while the peak densities of He* and N2+ both appear at the dielectric nozzle and the jet head. When N2 flow velocity is low, the Penning ionization rate is lower than the electron impact ionization rate, but when N2 flow velocity is high, it is just the opposite, which can increase the concentration of reactive species and contribute to the practical application of the jet. N2 flow velocity not only changes the length and structure of the jet but also controls the uniformity of the distribution of reactive species in the jet, which indicates that there is an optimal N2 flow velocity to make the jet longer and more uniform in space, which will greatly promote the practicality and flexibility of the plasma jet and also provide meaningful insights for optimizing and controlling the characteristics of the plasma jet.

Influence of operating conditions on electron density in atmospheric pressure helium plasma jets

“…Within the dielectric tube, plasma bullets begin as toroidal structures and then transform into solid structures as they propagate, leading to an enhanced axial ionization and electric field. This phenomenon is consistent with experimental and simulation findings [51,52]. When the propagation times were 30, 60, 95, and 180 ns, the plasma bullets reached 9, 19, 25.2, and 38.4 mm, respectively.…”

Study of spatiotemporal characteristics of atmospheric-pressure pulsed microwave Ar/N<sub>2</sub> plasma jets

“…有效降低等离子体射流的气体温度, 进而拓展了微波 等离子体射流的应用范围 [12] . 放电器进气结构的设计对等离子体射流特性也有 很大影响, 比如选用双气体通道结构的放电器, 产生的 等离子体射流尺度更长, 形态更丰富 [13,14] . Reuter课题 组 [15] 设计双气体通道结构的放电器, 内外通道分别输 入Ar和O 2 , 在射频电压激励下, 产生了更长尺度的等 离子体射流.…”

Discharge characteristics of atmospheric pressure pulsed microwave He/N2 plasma jet

“…[25][26][27][28][29][30][31][32][33] In addition, since the Penning effect is often found between N 2 and He, so it is important to investigate the plasma characteristics when N 2 and He are used as the working gas through the dualchannel stratified intake mode. Wang et al [27,28] have investigated the He/N 2 plasma jet under a low frequency which was driven by DC high-voltage. The results show that the length and structure of the plasma jet can be controlled by changing the flow rate of working gas, thereby improving the uniformity of jet distribution.…”

“…For example, when a dual-channel stratified intake mode is used, the scale of the plasma jet is longer and the morphology becomes richer. [25][26][27][28][29][30][31][32][33] In addition, since the Penning effect is often found between N 2 and He, so it is important to investigate the plasma characteristics when N 2 and He are used as the working gas through the dualchannel stratified intake mode. Wang et al [27,28] have investigated the He/N 2 plasma jet under a low frequency which was driven by DC high-voltage.…”