ARC discharge in a cross flow of gas
The experimental study of nonequilibrium air plasma flow of atmospheric pressure in the transverse arc discharge of high voltage is conducted. The high non-izothemality in the air plasma during its space evolution is shown in dependence on the gas flow rate and discharge energy deposition with a det...
Saved in:
| Date: | 2005 |
|---|---|
| Main Authors: | , , , , , , |
| Format: | Article |
| Language: | English |
| Published: |
Національний науковий центр «Харківський фізико-технічний інститут» НАН України
2005
|
| Series: | Вопросы атомной науки и техники |
| Subjects: | |
| Online Access: | http://dspace.nbuv.gov.ua/handle/123456789/79808 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Journal Title: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Cite this: | ARC discharge in a cross flow of gas / V.Ya. Chernyak, V.V. Naumov, V.V. Yukhymenko, I.L. Babich, V.A. Zrazhevskyy, Yu.V. Woewoda, T.V. Pashko // Вопросы атомной науки и техники. — 2005. — № 2. — С. 164-166. — Бібліогр.: 10 назв. — англ. |
Institution
Digital Library of Periodicals of National Academy of Sciences of Ukraine| id |
irk-123456789-79808 |
|---|---|
| record_format |
dspace |
| spelling |
irk-123456789-798082015-04-05T03:02:12Z ARC discharge in a cross flow of gas Chernyak, V.Ya. Naumov, V.V. Yukhymenko, V.V. Babich, I.L. Zrazhevskyy, V.A. Woewoda, Yu.V. Pashko, T.V. Low temperature plasma and plasma technologies The experimental study of nonequilibrium air plasma flow of atmospheric pressure in the transverse arc discharge of high voltage is conducted. The high non-izothemality in the air plasma during its space evolution is shown in dependence on the gas flow rate and discharge energy deposition with a detailed emission spectroscopic diagnostics of excited atoms, molecules and radicals along the plasma jet. Проведені експериментальні дослідження нерівноважної повітряної плазми атмосферного тиску в поперечному дуговому розряді високої напруги. З використанням спектрів випромінювання атомів, молекул та радикалів показана еволюція рівня неізотермічності в плазмі повітря в залежності від швидкості газового потоку та енергії, що вкладається в розряд. Проведены экспериментальные исследования неравновесной воздушной плазмы атмосферного давления в поперечном дуговом разряде высокого напряжения. С использованием спектров излучения атомов, молекул и радикалов показана эволюция уровня неизотермичности в плазме воздуха в зависимости от скорости газового потока и энерговклада в разряд. 2005 Article ARC discharge in a cross flow of gas / V.Ya. Chernyak, V.V. Naumov, V.V. Yukhymenko, I.L. Babich, V.A. Zrazhevskyy, Yu.V. Woewoda, T.V. Pashko // Вопросы атомной науки и техники. — 2005. — № 2. — С. 164-166. — Бібліогр.: 10 назв. — англ. 1562-6016 PACS: 52.80.-s; 52.80.Mg; 52.80.Wq; 52.77.Bn; 52.77.Fv http://dspace.nbuv.gov.ua/handle/123456789/79808 en Вопросы атомной науки и техники Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| institution |
Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| collection |
DSpace DC |
| language |
English |
| topic |
Low temperature plasma and plasma technologies Low temperature plasma and plasma technologies |
| spellingShingle |
Low temperature plasma and plasma technologies Low temperature plasma and plasma technologies Chernyak, V.Ya. Naumov, V.V. Yukhymenko, V.V. Babich, I.L. Zrazhevskyy, V.A. Woewoda, Yu.V. Pashko, T.V. ARC discharge in a cross flow of gas Вопросы атомной науки и техники |
| description |
The experimental study of nonequilibrium air plasma flow of atmospheric pressure in the transverse arc discharge of high voltage is conducted. The high non-izothemality in the air plasma during its space evolution is shown in dependence on the gas flow rate and discharge energy deposition with a detailed emission spectroscopic diagnostics of excited atoms, molecules and radicals along the plasma jet. |
| format |
Article |
| author |
Chernyak, V.Ya. Naumov, V.V. Yukhymenko, V.V. Babich, I.L. Zrazhevskyy, V.A. Woewoda, Yu.V. Pashko, T.V. |
| author_facet |
Chernyak, V.Ya. Naumov, V.V. Yukhymenko, V.V. Babich, I.L. Zrazhevskyy, V.A. Woewoda, Yu.V. Pashko, T.V. |
| author_sort |
Chernyak, V.Ya. |
| title |
ARC discharge in a cross flow of gas |
| title_short |
ARC discharge in a cross flow of gas |
| title_full |
ARC discharge in a cross flow of gas |
| title_fullStr |
ARC discharge in a cross flow of gas |
| title_full_unstemmed |
ARC discharge in a cross flow of gas |
| title_sort |
arc discharge in a cross flow of gas |
| publisher |
Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| publishDate |
2005 |
| topic_facet |
Low temperature plasma and plasma technologies |
| url |
http://dspace.nbuv.gov.ua/handle/123456789/79808 |
| citation_txt |
ARC discharge in a cross flow of gas / V.Ya. Chernyak, V.V. Naumov, V.V. Yukhymenko, I.L. Babich, V.A. Zrazhevskyy, Yu.V. Woewoda, T.V. Pashko // Вопросы атомной науки и техники. — 2005. — № 2. — С. 164-166. — Бібліогр.: 10 назв. — англ. |
| series |
Вопросы атомной науки и техники |
| work_keys_str_mv |
AT chernyakvya arcdischargeinacrossflowofgas AT naumovvv arcdischargeinacrossflowofgas AT yukhymenkovv arcdischargeinacrossflowofgas AT babichil arcdischargeinacrossflowofgas AT zrazhevskyyva arcdischargeinacrossflowofgas AT woewodayuv arcdischargeinacrossflowofgas AT pashkotv arcdischargeinacrossflowofgas |
| first_indexed |
2025-07-06T03:46:54Z |
| last_indexed |
2025-07-06T03:46:54Z |
| _version_ |
1836867769798230016 |
| fulltext |
LOW TEMPERATURE PLASMA AND PLASMA TECHNOLOGIES
ARC DISCHARGE IN A CROSS FLOW OF GAS
V.Ya. Chernyak1, V.V. Naumov2, V.V. Yukhymenko1, I.L. Babich1, V.A. Zrazhevskyy1,
Yu.V. Woewoda 1, T.V. Pashko 1
1Radiophysical Department, Taras Shevchenko Kyiv National University,
Volodymyrska st. 64, Kiev 01033, Ukraine, e-mail:chern@univ.kiev.ua;
2 Department of Photoactivity, Institute of Physics, Ukrainian Academy of Sciences,
Prospect Nauki 46, Kiev 03028, Ukraine, e-mail: kern@iop.kiev.ua
The experimental study of nonequilibrium air plasma flow of atmospheric pressure in the transverse arc discharge of
high voltage is conducted. The high non-izothemality in the air plasma during its space evolution is shown in
dependence on the gas flow rate and discharge energy deposition with a detailed emission spectroscopic diagnostics of
excited atoms, molecules and radicals along the plasma jet.
PACS: 52.80.-s; 52.80.Mg; 52.80.Wq; 52.77.Bn; 52.77.Fv
1. INTRODUCTION
Nonequilibrium air plasma in electric discharges is of
permanent interest in many labs because of various
important applications in plasma chemistry, materials
processing, energy- and eco-biotechnologies [1]. Non-
isothermality in plasma has a fundamental importance for
efficiency of plasma chemical processes, especially at
sub-atmospheric pressure conditions, when the
temperature of electrons is higher than the character
temperatures of heavy particles (ions, atoms, molecules,
and radicals). While most of the discharge energy is
directed into the energy of electrons and not just to gas
heating, it gives desirable selectivity of plasma chemical
transformations [2]. Among possible variants of non-
thermal high pressure discharges: spark, corona, barrier,
etc [3], one specific type is most interesting for us. This is
a transverse arc in a blowing flow with a stationary
current column or rotating in a vortex flow [4]. It is an
intermediate case of the high-voltage low-current self-
sustained discharge with a self-adjustable arc supported
by the plasma flow, which provides a high level of
ionization. It differs from the non-stationary gliding arc of
Czernichowski type [5-6] by the fixed arc length. It has
also a convective cooling of the plasma column by the air
flow but without conductive heat losses at walls since it is
a free arc jet. An intensive transverse ventilation of the
arc plasma increases its ionization, nonequilibrium and
non-izothermality. We successfully applied different
schemes of transverse blowing arc with primary and
secondary discharges in our current investigations in Kiev
University, carrying out plasma-assisted processing of
various homo- and heterophase gas and liquid substances
[7-9]. Despite of achievements in practical applications
there are still enough issues for research. The main point
is mechanism of transition from quasi-equilibrium arc
discharge to non-equilibrium, i.e. from thermal to non-
thermal ionization.
In this paper we like to present results of
spectroscopic characterization of the air plasma flow in
the transverse blowing arc discharge with the fixed arc in
order to get more deep understanding in the physics of
processes.
2. METHODOLOGY
Experiments have been done for a scheme of the
transverse blowing arc as shown in Fig.1. A free jet of
atmospheric air ran from the nozzle across two horizontal
opposite electrodes and formed a bright crescent-shaped
electric arc as well as a highly reactive afterglow. We
used the rod electrodes with diameter d = 5 mm. A
nominal gap between the electrodes from which we
started usually was δ = 1 mm. Since the electrodes were
not cooled, the electric discharge energy was transferred
totally to the air plasma flow. We applied electrodes made
from different materials: copper and graphite, in order to
see spectroscopic difference. The air nozzle was
axisymmetric, with inner diameter ∅ = 1 mm, made from
stainless steel. It was maintained vertically perpendicular
to the electrode axis at the length L = 5-10 mm and was
centered strictly between the electrodes. We used a
standard technical dry air system supply with the flow
meters. It was enough high gasdynamic pressure in the
flow to blow out the electric arc downstream. In fact, we
can regulate the arc discharge geometry as by the gap δ
164 Problems of Atomic Science and Technology. Series: Plasma Physics (11). 2005. № 2. P. 164-166
Z
0
Z
MDR-23
or
MOSAL > 5
Flens
Lens
Computer
Gas
Fig.1.
mailto:kern@iop.kiev.ua
between the electrodes and by the length L between the
nozzle exit and the electrodes. The last allows to control
both the air blowing of the arc and air cooling of the
electrodes. Then, we can regulate the air flow rate, G, and
arc discharge current, Id. The arc discharge is powered by
the DC source at the ballast resistance R = 2 kΩ in the
circuit. Electric current-voltage parameters were
measured with the standard electronics.
For optical diagnostics, the emission UV-VIS-NIR
spectroscopy was applied. Plasma radiation was measured
by two means: 1) portable rapid PC-operated CCD-based
multi-channel optical spectra analyzer (MOSA), which
has a wide wavelength survey (200-1100 nm) but medium
spectral resolution (~0.2 nm), and 2) spectral combine
KSVU-23, including a scanning monochromator (DMR-2),
PMT detector (FEU-100) and PC recorder, which
provides a high spectral resolution (up to 0.01 nm) but
low scanning speed. Measurements were conducted in
different cross-sections along the arc and afterglow. The
spatial resolution was of 0.1 mm. The images were
normally focused by quartz lens at the bench 5-focus
distance from the arc directly on the entrance slit of the
spectral device. With MOSA we used a fine optical fiber
with a microlens. For calibration, a set of etalon spectral
sources: mercury, deuterium, xenon and tungsten lamps
were applied.
Within available spectrum of wavelengths from 200 to
1100 nm we conducted monitoring of all remarkable
emissions and identified all basic atomic lines of N, O, H
as well as molecular bands of NO, N2, O2, OH, CO, CN
which we were able to recognize. For analytical
diagnostics, we utilized relative intensities of analytical
CuI lines (in case of copper electrodes) and N2 2+-system
bands in order to determine the temperature of excitation
of electronic states of Cu atoms, Te, and the temperature
of excitation of vibrational states of N2 molecules, TV, as
commonly accepted method in case of optically thin
plasma [10]. The temperature of excitation of rotational
states, TR, because of non-resolved rotational spectral
structure at conditions of atmospheric pressure, was
estimated by comparison of the measured spectra of
N2 2+(0,0) band at 337.1 nm and the corresponding
synthetic spectra calculated on the known spectral
constants for N2 C3Πu-B3Πg E-V-R transitions, using the
Gauss-like instrumental function. On this base, we draw
curves of changes of the specific emission intensities
along the plasma, depending on the arc discharge power
and the air flow rate.
3. RESULTS AND DISCUSSIONS
A transverse arc discharge in the air flow was ignited
with a high voltage at the shortest distance between the
electrodes that corresponds to breakdown when the
electric field reached ~3 kV/mm [3]. Under the action of
gasdynamic pressure of the incident air flow, the electric
arc was forced to bow down and elongated along the
stream, so that the current increased and the voltage
dropped down a little bit. The air flow led not only to
bending and blowing of the arc current channel but also to
stabilization of the plasma column due to the convective
withdrawal of energy (radiative losses are neglected). Due
to a high speed flow, the air plasma had to be turbulized,
and it additionally contributed to suppression of
ionization-overheating instability. Thus, gas dynamics
and convective heat/mass transfer favored the steady-state
arc burning. The resulting current-voltage characteristics
of the blowing arc discharge have a typical for the high-
voltage high-pressure arc dropping character. It is
practically independent on the flow rate of the plasma-
forming gas at the given geometry of electrodes. It points
out that the transverse arc has a self-adjusting length and
the current channel is autostable in the air plasma flow
despite of visible non-uniformity and fluctuations in time
and in space.
The emission spectrum of of air plasma flow is rich of
spectroscopic information. We recognized here nitride
oxide NO γ-system (A2Σ+-X2Π: (0-0) 226.9 nm, (0-1)
236.3 nm, (0-2) 247.1 nm, etc); hydroxyl OH UV system
(A2Σ-X2Π: (0-0) 306.4-308.9 nm); oxy-gen O2 Shumann-
Runge bands (B3Σ-
u-X3Σ-
g: (0-14) 337.0 nm); nitrogen N2
+
1- system (B2Σ+
u-X2Σg
+: (1-0) 358.2, (1-1) 388.4, (0-0)
391.4 nm, etc); N2 2+ system (C3Πu-B3Πg: (0-0) 337.1, (0-
1) 357.7, (0-2) 380.5, (1-0) 316.0 nm, etc); and even week
N2 1+ system (B3Πg-A3Σ-
u: 570-750 nm). Among atomic
lines, we recognized HI Balmer α line 656.3 nm, OI lines
(777.3, 844.6, 926.0 nm), and NI lines (746.8, 818.8,
868.3 nm). There are a lot of Cu lines due to evaporation
of copper electrodes (in case of graphite we saw nothing),
but intensities of the most strong CuI lines 324.7 and
327.4 nm were overlap with N2
+ 1(-) bands, therefore we
used CuI lines 465.1, 510.5, 515.3, 521.8, and 578.2 nm.
The interference of N2 2+ system also precluded
diagnostics of OH (A-X) band at 308 nm.
All dependencies of emission intensities Iλ for the CuI
line and Iλ (z) for the N2 2+ and spectral distributions along
the z-axe downstream Iλ(z) are of non-linear character.
The comparison of IλCu (z) and IλN2 (z) tells that IλN2 (z)
distributions are sufficiently larger and are somewhat
shifting downstream relatively to IλCu (z).
On the base of the measured values IλCu (465.1, 510.5,
515.3, 521.8, 578.2 nm) and IλN2 (337.1, 353.6, 357.7,
371, 375.5, 380.5 nm) using the Boltzmann plot, we
determined corresponding temperatures of electronic
excitation of Cu atoms, Te, and vibrational excitation of
N2 molecules, TV. As expected, these temperatures
differenced very much. At that, the level of non-
izothermality is not permanent along the plasma flow. It
depends not only on the current of arc discharge but also
on the velocity of air flow that is blowing the arc plasma
column, providing convective heat/mass transfer.
Especially large differences occur in afterglow.
Along the flow the temperature Te is 0.7-0.6 eV while the
temperature TV is 0.4-0.35 eV. In the afterglow, Te
decreases while TV keeps longer. Then increasing the
discharge current Id, the temperature Te becomes larger.
At a lager flow rate G the gradient Te becomes smaller.
The non-equilibrium of air plasma in the blowing arc
discharge follows also from the estimation of rotational
temperature TR obtained at the same conditions. Fig. 2
shows the results of simulation of V-R spectra for the
N2 2+(0-0) band 337.1 nm, calculated at different TR =
0,05-0,5 eV with the step of 0,05 eV (from curve 1 that is
165
TR = 0,05 eV to curve 10 that is TR = 0.5 eV), as compared
with the measured data in the discharge at Id = 200 mA for
G = 40 cm3/s (curve 11) and 80 cm3/s (curve 12) at the
distance z ≈ 7 mm. Our estimation of TR is 0,2–0,25 eV. It
differenced from TV more then twice. This evidences
about really strong non-isothermality in afterglow.
4. CONCLUSIONS
We see that a high-voltage low-current transverse
blowing arc discharge in the air flow of atmospheric
pressure can be a source of non-isothermal plasma with a
high level of ionization. We found that there is no local
LTE in this arc discharge air plasma flow during its
space/time evolution, and the measured/estimated
temperatures of electrons and molecular states are within
the relations Te ~ Texc > TV > TR ~ Tg. The temperature of
electron excitation of heavy particles Texc undertaken
through the partially resolved emission of N2
+ 1(-) bands
differenced from the temperature of vibrationally and
rotationally excited molecules more then twice.
Therefore, usual two-temperature approach with Te for
electrons and Tg for heavy particles is not valid here.
Another character effect is an “ignition” of the molecular
emission downstream the arc resulted from the kinetic
non-equilibrium conditions. The highest temperature
(~1.5 eV) is measured in the center of the arc. In the
afterglow zone, the temperature Te decreases rapidly
while the temperature of excited metastable molecules Texc
keeps longer. The factors, which effects on plasma
nonequilibrium are not only electric parameters of arc
discharge but also gas dynamics and convective heat/mass
transfer in the plasma flow. Due to suppression of
ionization-overheating instabilty at highly turbulized
flow, the plasma space and its interaction with
environment can be increased significantly. Taking into
account high plasma density, high electron temperature,
easy control of discharge potential and possibility of
stimulation of selective chemical reactions at relatively
low gas temperatures, we may conclude that this type of
nonequilibrium arc discharge is very suitable for
technological applications including plasma-assisted
ignition/combustion of gas-liquid hydrocarbon fuels and
plasma-enhanced modification of combustion products.
REFERENCES
1. Proc. 16th Intern. Symp. on Plasma Chemistry,
Taormina, Italy /Eds. M.Capitelli et al., 2003 and
Proc. 3rd Symp. on Theoretical and Applied Plasma
Chemistry, Plyos, Russia /Eds. D.I.Slovetsky et al.,
Moscow. 2002.
2. V.D. Rusanov, A.A. Fridman. Physics of Chemically
Active Plasma. Moscow: “Nauka”, 1984.
3. Yu.P.Raiser. Gas Discharge Physics. Berlin: Springer,
1997.
4. V.Ya. Chernyak // Proc. 3rd Intern. Seminar on
Electrophysical and Thermophysical Processes in
Low-Temperature Plasma. Brno, 1999, p.94-99.
5. A.Czernichowski // Pure & Appl. Chem. 1994, 66(6),
p.1301-1310.
6. A. Fridman, S. Nester, L.A. Kennedy, A. Saveliev,
O.Mutaf-Yardimci // Prog. Energy. Combust. Sci.
1999, v.25, p.211- 232.
7. V.Ya.Chernyak, V.V.Buchnev, S.D.Koval, et al. //
Nonequilibrium Processes and their Applications,
HMTI, Minsk, 2000, p.75-78
8. V. Chernyak, S. Koval, V. Naumov // Proc. 15th
Intern. Symp. on Plasma Chemistry /Eds.
A.Bouchoule, J.-M.Pouvesle. GREMI, Orleans, 2001,
v. IV, p.1447-1452.
9. V.Ya. Chernyak // Bull. Kyiv University. Series:
Physics, 2002, 4 (1), p.362-370.
10. V. Zhivotov, V. Rusanov, A. Fridman. Diagnostics of
Non-Equilibrium Chemically Active Plasma. Moscow:
“Atomizdat”, 1985.
ДУГОВОЙ РАЗРЯД В ПОПЕРЕЧНОМ ПОТОКЕ ГАЗА
В.Я. Черняк, В.В. Наумов, В.В. Юхименко, И.Л. Бабич, В.А. Зражевский, Ю.В. Воевода, Т.В. Пашко
Проведены экспериментальные исследования неравновесной воздушной плазмы атмосферного давления в
поперечном дуговом разряде высокого напряжения. С использованием спектров излучения атомов, молекул и
радикалов показана эволюция уровня неизотермичности в плазме воздуха в зависимости от скорости газового
потока и энерговклада в разряд.
ДУГОВИЙ РОЗРЯД У ПОПЕРЕЧНОМУ ПОТОЦІ ГАЗУ
В.Я. Черняк, В.В. Наумов, В.В. Юхименко, І.Л. Бабіч, В.А. Зражевський, Ю.В. Воєвода, Т.В. Пашко
Проведені експериментальні дослідження нерівноважної повітряної плазми атмосферного тиску в
поперечному дуговому розряді високої напруги. З використанням спектрів випромінювання атомів, молекул та
радикалів показана еволюція рівня неізотермічності в плазмі повітря в залежності від швидкості газового
потоку та енергії, що вкладається в розряд.
166
|