04aE02P
プラズマを伴う中性期待噴流の乱流化の解明に向けた研究
Study on turbulence phenomena of the neutral gas flow induced by the plasma production
山岸祐介 1,2, 榊田創 1,2, 角田秀一郎 1, 笠原次郎 3, 金載浩 2, 池原譲 2, 山田大将 1,2, 久保田昭貴子 2, 木山学 2
Yusuke Yamagishi1,2, Hajime Sakakita1,2, Syuichiro Tsunoda1, Jiro Kasahara3, Jaeho Kim2, Yuzuru Ikehara2,
Hiromasa Yamada1,2, Akiko Kubota2, and Satoru Kiyama2
1

筑波大院システム情報，2 産総研，3 名古屋大院工1
Univ. of TSUKUBA, 2 AIST, 3 NAGOYA Univ.

1.

Introduction
Recently, plasma production experiments have been
carried out under atmospheric-pressure with the aim ofapplying the results to improved combustion1), medicalequipments2,3), material surface processing, and so forth. In
many cases, the atmospheric-pressure plasma is produced
using rare gases or nitrogen4), which flow through theequipment5). The typical gas flow speed is in the range of 1 –10 m/s, which is much slower than that of a plasma jet.
Interaction phenomena between charged particles and neutral
particles are very important, since the particle number of
ambient gases is much larger than that of charged particles. In
this study, we visualized the behavior of neutral gases along aplasma jet using a Schlieren optical system with a high-speed
camera under several conditions.
2.

Experimental Setups
A Schlieren optical system and a high-speed video
camera are used for visualization study of neutral gas flow.
The former is composed of continuum light source (Xe lump)and convex lens, pinhole and concave lens, knife edge. The
later is using Shimadzu HTV-1, interframe time is set up
between 4 μs-16 ms, and expose time is set up 1/8 times ofinterframe time. The image resolution was 312 (horizontal) ×
260 (vertical) pixels.
In our experiments, a plasma equipment based on thedielectric barrier discharge is used6). A cylindrical quartz tube
used as a dielectric, and the gas flows through the tube. A
powered electrode is installed in part of the dielectric, and iscompletely covered by the dielectric and a grounded electrode.
This type of plasma source produces glow like plasma withgood directivity that in principle, does not undergo atransition to an arc discharge.
To study dependencies of neutral gas flow characteristics
on the electrostatic effect, copper electrode is arranged asFig. 1. Schematic drawing of an arrangement to study theelectrostatic effect on the neutral gas flow. In thisexperiment, the copper plate is grounded.

schematically illustrated in Fig. 1. A stainless bolt is coveredby the kapton polyimide film, and a plate is fixed by theinsulated nuts. Nozzle of the plasma equipment is set parallelto the copper plate.
3.

Experimental Results
The helium gas flow parallel to the copper plate without
the plasma discharge was found laminar flow and straight
behavior. The helium gas flow parallel to the copper platewith the plasma discharge was found that not only the plasmajet, but also neutral helium gas flow bent toward a copper
plate. Here, the plate is grounded, gas flow rate is 1 l/min, anddistance between the copper plate and the nozzle axis line is6 mm.
At present, to understand interaction phenomena
between neutral gas flow and charged particles, dependenciesof neutral gas flow on the electrostatic force are studied.
4.

Conclusions
We visualized the behavior of neutral gases along aplasma jet using a Schlieren optical system with a high-speed
camera. In the result, not only the plasma jet, but also neutral
helium gas flow bent toward a grounded copper plate.
Acknowledgements
We thank to Dr. K. Matsuoka at Nagoya University, andMr S.Sumiya at University of Tsukuba. This study wasfinancially supported by JSPS KAKENHI Grant Number
24108006, and in part by the Japan Society for the Promotionof Science Core-to-Core Program 22001.
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