Thermal radiation in spark discharge
The work is devoted to numerical study on thermal radiation in spark discharge. The influence of radiative thermal conductivity on the expansion of the spark channel has been established. The study of the effect of value of the capacitance of the discharge capacitor on the energy emitted by the disc...
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| Cite this: | Thermal radiation in spark discharge / K. Korytchenko, E. Poklonskiy, D. Samoilenko, D. Vinnikov, R. Meleshchenko, K. Ostapov // Problems of Atomic Science and Technology. — 2021. — № 4. — С. 171-176. — Бібліогр.: 17 назв. — англ. |
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Korytchenko, K. Poklonskiy, E. Samoilenko, D. Vinnikov, D. Meleshchenko, R. Ostapov, K. 2023-12-05T10:11:38Z 2023-12-05T10:11:38Z 2021 Thermal radiation in spark discharge / K. Korytchenko, E. Poklonskiy, D. Samoilenko, D. Vinnikov, R. Meleshchenko, K. Ostapov // Problems of Atomic Science and Technology. — 2021. — № 4. — С. 171-176. — Бібліогр.: 17 назв. — англ. 1562-6016 PACS: 52.80.Mg DOI: https://doi.org/10.46813/2021-134-171 https://nasplib.isofts.kiev.ua/handle/123456789/195426 The work is devoted to numerical study on thermal radiation in spark discharge. The influence of radiative thermal conductivity on the expansion of the spark channel has been established. The study of the effect of value of the capacitance of the discharge capacitor on the energy emitted by the discharge has been carried out. The change in the thermodynamic state of the gas in the spark channel is considered taking into account following factors: change in the capacitance of the discharge capacitor, the length of the discharge gap and the initial gas pressure. The influence of the initial gas pressure and the gap length on the parameters of thermal radiation of a gas under conditions of a constant breakdown voltage supplied to the spark gap is investigated. Робота присвячена чисельному дослідженню теплового випромінювання в іскровому розряді. Встановлено вплив променистої теплопровідності на розширення іскрового каналу. Проведено дослідження впливу величини ємності розрядного конденсатора на енергію, що випромінюється розрядом. Розглянуто зміну термодинамічного стану газу в іскровому каналі з урахуванням наступних факторів: зміни ємності розрядного конденсатора, довжини розрядного проміжку і початкового тиску газу. Вивчено вплив початкового тиску газу і довжини проміжку на параметри теплового випромінювання газу в умовах постійної напруги пробою іскрового проміжку. Работа посвящена численному исследованию теплового излучения в искровом разряде. Установлено влияние лучистой теплопроводности на расширение искрового канала. Проведено исследование влияния величины емкости разрядного конденсатора на энергию, излучаемую разрядом. Рассмотрено изменение термодинамического состояния газа в искровом канале с учетом следующих факторов: изменения емкости разрядного конденсатора, длины разрядного промежутка и начального давления газа. Изучено влияние начального давления газа и длины промежутка на параметры теплового излучения газа в условиях постоянного напряжения пробоя искрового промежутка. en Національний науковий центр «Харківський фізико-технічний інститут» НАН України Вопросы атомной науки и техники Gas discharge, plasma-beam discharge, and their applications Thermal radiation in spark discharge Теплове випромінювання в іскровому розряді Тепловое излучение в искровом разряде Article published earlier |
| institution |
Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| collection |
DSpace DC |
| title |
Thermal radiation in spark discharge |
| spellingShingle |
Thermal radiation in spark discharge Korytchenko, K. Poklonskiy, E. Samoilenko, D. Vinnikov, D. Meleshchenko, R. Ostapov, K. Gas discharge, plasma-beam discharge, and their applications |
| title_short |
Thermal radiation in spark discharge |
| title_full |
Thermal radiation in spark discharge |
| title_fullStr |
Thermal radiation in spark discharge |
| title_full_unstemmed |
Thermal radiation in spark discharge |
| title_sort |
thermal radiation in spark discharge |
| author |
Korytchenko, K. Poklonskiy, E. Samoilenko, D. Vinnikov, D. Meleshchenko, R. Ostapov, K. |
| author_facet |
Korytchenko, K. Poklonskiy, E. Samoilenko, D. Vinnikov, D. Meleshchenko, R. Ostapov, K. |
| topic |
Gas discharge, plasma-beam discharge, and their applications |
| topic_facet |
Gas discharge, plasma-beam discharge, and their applications |
| publishDate |
2021 |
| language |
English |
| container_title |
Вопросы атомной науки и техники |
| publisher |
Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| format |
Article |
| title_alt |
Теплове випромінювання в іскровому розряді Тепловое излучение в искровом разряде |
| description |
The work is devoted to numerical study on thermal radiation in spark discharge. The influence of radiative thermal conductivity on the expansion of the spark channel has been established. The study of the effect of value of the capacitance of the discharge capacitor on the energy emitted by the discharge has been carried out. The change in the thermodynamic state of the gas in the spark channel is considered taking into account following factors: change in the capacitance of the discharge capacitor, the length of the discharge gap and the initial gas pressure. The influence of the initial gas pressure and the gap length on the parameters of thermal radiation of a gas under conditions of a constant breakdown voltage supplied to the spark gap is investigated.
Робота присвячена чисельному дослідженню теплового випромінювання в іскровому розряді. Встановлено вплив променистої теплопровідності на розширення іскрового каналу. Проведено дослідження впливу величини ємності розрядного конденсатора на енергію, що випромінюється розрядом. Розглянуто зміну термодинамічного стану газу в іскровому каналі з урахуванням наступних факторів: зміни ємності розрядного конденсатора, довжини розрядного проміжку і початкового тиску газу. Вивчено вплив початкового тиску газу і довжини проміжку на параметри теплового випромінювання газу в умовах постійної напруги пробою іскрового проміжку.
Работа посвящена численному исследованию теплового излучения в искровом разряде. Установлено влияние лучистой теплопроводности на расширение искрового канала. Проведено исследование влияния величины емкости разрядного конденсатора на энергию, излучаемую разрядом. Рассмотрено изменение термодинамического состояния газа в искровом канале с учетом следующих факторов: изменения емкости разрядного конденсатора, длины разрядного промежутка и начального давления газа. Изучено влияние начального давления газа и длины промежутка на параметры теплового излучения газа в условиях постоянного напряжения пробоя искрового промежутка.
|
| issn |
1562-6016 |
| url |
https://nasplib.isofts.kiev.ua/handle/123456789/195426 |
| citation_txt |
Thermal radiation in spark discharge / K. Korytchenko, E. Poklonskiy, D. Samoilenko, D. Vinnikov, R. Meleshchenko, K. Ostapov // Problems of Atomic Science and Technology. — 2021. — № 4. — С. 171-176. — Бібліогр.: 17 назв. — англ. |
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2025-11-25T21:31:27Z |
| last_indexed |
2025-11-25T21:31:27Z |
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| fulltext |
ISSN 1562-6016. ВАНТ. 2021. № 4(134) 171
https://doi.org/10.46813/2021-134-171
THERMAL RADIATION IN SPARK DISCHARGE
K. Korytchenko1, E. Poklonskiy2, D. Samoilenko3, D. Vinnikov4, R. Meleshchenko5,
K. Ostapov5
1National Technical University “KhPI”, Kharkiv, Ukraine;
2V.N. Karazin Kharkiv National University, Kharkiv, Ukraine;
3Warsaw University of Technology, Warsaw, Poland;
4National Science Center “Kharkov Institute of Physics and Technology”, Kharkiv, Ukraine;
5National University of Civil Defence of Ukraine, Kharkiv, Ukraine
E-mail: korytchenko_kv@ukr.net
The work is devoted to numerical study on thermal radiation in spark discharge. The influence of radiative
thermal conductivity on the expansion of the spark channel has been established. The study of the effect of value of
the capacitance of the discharge capacitor on the energy emitted by the discharge has been carried out. The change
in the thermodynamic state of the gas in the spark channel is considered taking into account following factors:
change in the capacitance of the discharge capacitor, the length of the discharge gap and the initial gas pressure.
The influence of the initial gas pressure and the gap length on the parameters of thermal radiation of a gas under
conditions of a constant breakdown voltage supplied to the spark gap is investigated.
PACS: 52.80.Mg
INTRODUCTION
As a source of thermal radiation, a high-current
spark discharge is used in various processes. For exam-
ple, a spark discharge is used for pulsed photolysis and
ultrafast photography. Also, a spark discharge is ap-
plied to simulate high-temperature radiation-
gasdynamic phenomena and in brightness standards.
It is known that during the discharge of a capacitor
through the spark gap, only a part of the discharge en-
ergy is released in the gas-discharge channel [1]. The
energy released at the spark gap is distributed into ther-
mal energy, kinetic energy of the gas flow, absorbed by
dissociation and ionization processes, and part of the
energy is emitted by electromagnetic radiation. As a
result, only part of the discharge energy is radiated. It is
of interest to establish the influence of the initial condi-
tions of the discharge and the parameters of the dis-
charge circuit on the efficiency of thermal radiation of
the spark channel.
The study of the thermal radiation of the spark
channel is presented in [2], where the dependence of
the effective radiation temperature on the discharge
time is established. Experimental confirmation of the
influence of the initial gas pressure on the brightness of
the spark discharge radiation was made in [3]. In [4],
the influence of the gas type (Xe, Kr, Ar, air, N2, Ne,
and He) on the limiting gas temperature which leads to
saturation of the radiation brightness was investigated.
In a number of works, the influence of the length of the
spark gap on the energy input into the spark channel
was also established. And in the works [5, 6] the influ-
ence of the parameters of the electric discharge circuit
on the efficiency of energy input into the spark channel
was shown.
Numerical models have been developed to study the
development of a spark channel during its expansion [7
-13]. The known models take into account the processes
of gas-dynamic expansion of the spark channel, non-
equilibrium chemical reactions, ionization, thermal
conductivity, and radiation. Among mentioned models,
there are models [2 - 4], which take into account radia-
tive heat conductivity. But the contribution of radiative
thermal conductivity to the expansion of the spark
channel was not considered in these works.
The current study is carried out using the developed
numerical model of the spark channel expansion [14 -
16]. In earlier works, the model was validated in the
range of spark discharge energies from tens of micro-
joules to hundreds of joules. Additionally, among other
influences, the influence of discharge conditions on the
process of thermal radiation by a spark channel was
studied in these works. Due to the fact that such studies
have been published in different works, a comprehen-
sive understanding of the process of thermal radiation
in a spark channel is shown in this work.
NUMERICAL MODEL
OF SPARK CHANNEL EXPANSION
The Euler's equations of gas-dynamics for one-
dimensional problems endowed with cylindrical sym-
metry was solved for the multicomponent chemically
reactive gas mixture (molecular and atomic nitrogen).
Taking into account that the model was described pre-
viously in works [14 - 16], we give equations in this
work that connected with radiative process only. So,
this process is considered by equation
2 2
2
em
2 21
,
T
u dT ur u p k
dt
r r t
E W
(1)
where ρ is the gas density; u is the velocity, p is the
pressure, ε is the specific internal energy of the gas, kT
is the thermal conductivity, E is the electric field
strength, σ is the electrical conductivity of the gas, Wem
is the radiative loss, r is the radial coordinate, t is the
ISSN 1562-6016. ВАНТ. 2021. № 4(134) 172
time, T is the gas temperature.
The radiative loss was calculated using the expres-
sion
RSBem l/ТW 4 , (2)
where σSB is the Stefan–Boltzmann constant, lR is the
Rosseland mean free path. The equation (2) was ap-
plied when the gas temperature exceeds 8.000 K.
In the model the heat conductivity coefficient was
calculated using the expression of
radelr kkk , (3)
where kel is a coefficient of electronic heat conductivity;
krad is a coefficient of radiative heat conductivity.
The coefficient krad of radiative heat conductivity
was calculated using the expression of
RSBrad lTk 3
3
16
. (4)
The numerical model (1-20) can be applied when
gas-dynamic pressure exceeds the magnetic pressure by
an order of magnitude. Description of the simulation
procedure is presented in works [15, 16].
The gradients of thermodynamic gas parameters are
assumed to be absent for the spark channel axis. It is
assumed that initial conditions have no gas dynamic
perturbations in the entire computation region.
The validation of the model for thermal radiation of
spark discharge is done in [14].
INFLUENCE OF RADIATIVE THERMAL
CONDUCTIVITY ON SPARK EXPANSION
To carry out these studies, the calculation of the
change in the temperature and density distribution
along the radial coordinate of the spark channel was
carried out under conditions when radiative thermal
conductivity is included and excluded. Thus, the heat
conductivity coefficient was represented by an equation
in the form kr = kel + krad or kr = kel.
The results of calculating the distribution of the
thermodynamic parameters of the gas in the spark dis-
charge for a channel expansion time of 30 and 100 ns
and for the discharge of a capacitor with a capacitance
of C = 1 μF charged at a voltage of 30 kV over a gap
length of 10 mm are shown in Fig. 1. In both simula-
tion variants, it was assumed that the inductance of the
discharge circuit is L = 2 μH, and the resistance of the
electric circuit is Rc = 0.3 Ω. The calculation was car-
ried out for a discharge in nitrogen at an initial gas
temperature T0 = 300 K and an initial gas pressure p0 =
101.4 kPa. To form a conductive channel, during 10 ns
the energy equal to 22 mJ was deposited into the com-
putational domain with a radius of 0.1 mm.
Fig. 1. Distribution of gas temperature and density
along the radial coordinate for a time of 30 and 100
ns: 1 – excluding radiative thermal conductivity;
2 – including radiative heat conductivity
According to the simulation results, it was found
that if the radiative thermal conductivity is not taken
into account, then during 100 ns, 135 mJ energy is in-
troduced into the spark channel, and due to electro-
magnetic radiation, 35 mJ leaves the discharge. If ra-
diative thermal conductivity is taken into account, an
energy of 215 mJ is introduced into the spark channel
for a time of 100 ns, and 1.8 mJ leaves with radiation.
From the presented research result follows that if
the radiative thermal conductivity is not taken into ac-
count, the gas temperature would rises in the spark dis-
charge up to values that not correspond to the of ex-
perimental studies results. For example, in calculations,
for a time of 100 ns, the gas temperature exceeds
100.000 K. It is observed, on the other hand, that when
radiative thermal conductivity is taken into account, the
expansion rate of the spark channel increases. As a
result of this expansion, there is a decrease in the gas
temperature reached in the discharge. In the presented
calculation, where radiative thermal conductivity was
taken into account, the gas temperature for a time of
100 ns does not exceed 23.400 K. Thus, the intensive
expansion of the high-temperature region of the spark
channel is provided not only as a result of gas-dynamic
processes, but also due to radiative thermal conductiv-
ity.
INFLUENCE OF THE CAPACITOR
CAPACITANCE ON THE EMITTED ENERGY
This study was carried out for the discharge across a
spark gap with a length of lsp = 10 mm using capacitors
of different capacitances. In the calculations, the ca-
pacitance C of the capacitor was 0.01, 0.05, 0.1, 0.5,
and 1 μF. The capacitor charge was equal to U0 = 30
kV. Thus, the total discharge energy varied in the range
from 4.5 to 450 J. The other parameters of the electric
circuit did not change. Thus, the resistance of the dis-
charge circuit was Rc = 0.3 Ω, the inductance of the
circuit was L = 2 μH. Nitrogen was considered as a
working gas at an initial temperature of T0 = 300 K and
an initial gas pressure p0 = 101.4 kPa. To form a con-
ductive channel, an energy of 22 mJ was deposited into
the computational domain with a radius of 0.1 mm for
10 ns.
Calculation results of the energy Qrad emitted by the
spark discharge as function of time for different capaci-
tance of the capacitor are shown in Fig. 2.
ISSN 1562-6016. ВАНТ. 2021. № 4(134) 173
Fig. 2. Time dependence of the energy emitted
by the spark discharge for different capacitances
of the discharge capacitor
As it can be seen from the obtained result, in the
case of an increase in the capacitance of the capacitor
there is an increase in the energy emitted by the spark
discharge for the same spark development time. We
also observe that in the initial period of the spark chan-
nel expansion (from 0 to 300…500 ns), a small amount
of energy leaves with radiation. This is due to the small
volume of gas that radiates in the spark discharge for a
given period of time.
Let’s estimate instantaneous efficiency ηrad of ther-
mal radiation using the following equation
%
CU
tQrad
rad 1002
2
0
. (5)
Calculation results for instantaneous efficiency of
thermal radiation and different capacitor capacitances
is shown in Fig. 3.
Fig. 3. Instantaneous efficiency of thermal radiation
for different capacitances of the discharge capacitor
It can be seen from the obtained results, that in the
case of an increase in the capacitance of the capacitor,
the instantaneous efficiency of thermal radiation de-
creases. In particular, when the capacitance is C =
1 μF, we have ηrad = 0.82% for the time t = 10 μs, and
when the capacitance is C = 0.01 μF, we have ηrad =
5.8%. It should be noted that at a fixed time there is a
difference in the share of energy released during the
discharge for different capacitances. In particular, ac-
cording to the results of calculations at C = 0.01 μF for
a time of 10 μs, about 97 % of the total energy of the
discharge is released in the discharge on the resistance
of the electric circuit and the spark channel. With a
capacitance C = 1 μF for a time of 10 μs, about 77% of
the total energy is released in the discharge. Therefore,
the total efficiency of thermal radiation may differ from
the instantaneous efficiency.
Since the radiated energy is only a part of the en-
ergy deposited into the spark channel, the dependence
of the energy deposited into the discharge on the ca-
pacitance of the discharge capacitor was investigated.
The change in the energy released into the discharge
versus the discharge time was calculated using the
equation.
rdrdtElQ spdep 22 . (6)
The results of calculating the energy Qdep intro-
duced into the discharge as function of the discharge
time are shown in Fig. 4. We observe that an increase
in the capacitance of the capacitor leads to an increase
in the energy released into the spark channel. For ex-
ample, for a time of 10 μs, Qdep = 23.9 J of energy was
deposited into the spark discharge at a capacitance of C
= 1 μF, that is 5.3% of the total discharge energy. And
with a capacitance C = 0.01 μF, Qdep = 2.55 J is re-
leased for 10 μs, that is 56.6% of the total discharge
energy. It should be noted that the decrease in the effi-
ciency of energy deposition into the spark discharge in
the case of an increase in the capacitance of the dis-
charge capacitor was experimentally confirmed in [17].
Fig. 4. Dependence of the energy introduced into
the spark channel on the discharge time at different
capacitances of the discharge capacitor
From the results of comparing the curves of the ra-
diated energy (see Fig. 2) and the corresponding curves
of the deposited energy (see Fig. 4), we can conclude
that the radiated energy does not linearly depend on the
energy released into the spark channel.
To establish the relationship between the deposited
energy and the radiated energy at the given time, it was
calculated relative efficiency ηrel of the thermal radia-
tion
%
Q
Q
dep
rad
rel 100 . (7)
Calculation results for relative efficiency are shown
in Fig. 5.
It is observed that during the development of the
discharge, the share of the radiated energy in the total
energy released in the spark channel at the current time
increases. Moreover, with an increase in the capaci-
tance of the capacitor, the relative efficiency increases
to large values. It was found out that at the initial pe-
riod of the discharge development, the relative effi-
ciency for the same time interval practically coincides
for different capacitor capacitances. This coincidence
takes place for capacitance C = 0.01 μF and capaci-
tance C = 1 μF in the time interval from 0 to 400 ns.
For capacitors of C = 0.5 and 1 μF, there is a coinci-
dence for 3.5 μs.
ISSN 1562-6016. ВАНТ. 2021. № 4(134) 174
Fig. 5. Dependence of relative efficiency of the thermal
radiation from time at different capacitances
of the discharge capacitor
To understand the processes that lead to a change in
the energy emitted by the spark discharge at different
capacitances of the discharge capacitor, we considered
the change in the thermodynamic state of the gas in the
spark channel. The results of calculating the distribu-
tion of gas pressure and temperature for different times
along the radial coordinate of the spark channel in the
case of capacitor capacitances equal to C = 0.1 and 1
μF are shown in Figs. 6, 7.
Fig. 6. Distributions of pressure and temperature
as function of time, along the radial coordinate
of the spark channel when C = 0.1 μF
Fig. 7. Distributions of pressure and temperature
as function of time, along the radial coordinate
of the spark channel when C = 1 μF
As a result of comparing the distributions of the
thermodynamic parameters of the gas, it can be con-
cluded that in the case of an increase in the capacitance
of the capacitor, the temperature increases, which is
reached in the spark discharge for the same time. For
example, for a time of 1 μs at C = 0.1 μF, the maxi-
mum gas temperature is 19.000 K, and at C = 1 μF,
there is a temperature of 22.300 K. An increase in the
capacitance of the capacitor also leads to an increase in
the expansion rate of the spark channel. For example,
for a time of 10 μs at C = 0.1 μF, the radius of the con-
ductive (emitting) spark channel reaches 8 mm, and at
C = 1 μF, this radius is 12 mm. As a result of an in-
crease in the volume and temperature of the emitting
gas in the spark channel, the energy emitted by the dis-
charge increases.
A decrease in the energy input into the spark chan-
nel in the case of an increase in capacitance is associ-
ated with a change in the balance of energy release in
the spark gap and the resistance of the electrical circuit.
Therefore, the study of the effect of the capacitance of
the discharge capacitor on the change of the resistance
of the spark channel that is changed in time was carried
out. The results of calculating the change in the resis-
tance of the spark channel are shown in Fig. 8. For
further comparison, Fig. 8 also shows a line reflecting
the resistance of the electrical circuit equal to 0.3 Ω. It
is observed that only when a capacitor with a capaci-
tance of 0.01 μF is discharged, the spark resistance is
practically equal to the resistance of the discharge elec-
tric circuit. In this case, 50% of the total discharge en-
ergy is released in the spark channel. Therefore, with a
decrease in the resistance of the spark channel, which
arises in the case of an increase in the capacitance of
the capacitor, it leads to a decrease in the share of the
energy released in the spark channel from the total dis-
charge energy.
Fig. 8. Change in the resistance of the spark channel
as function of time at different capacitances
of the discharge capacitor
Let us analyse the relationship between the dis-
charge current and the energy introduced into the spark
channel and the radiated energy. The discharge current
arising in an electric circuit with a different capacitance
that is shown in Fig. 9. Comparison of the time varia-
tion of the change in the discharge current from the
radiated energy (see Fig. 2) and input energy (see Fig.
4) shows that current pulses are more influenced on the
energy input into the discharge than on the radiated
energy. In particular, when the current values pass
through zero, the termination of energy input into the
discharge channel is observed, and at the maximum
current we observe a maximum of the energy input
power (see Fig. 4).
Fig. 9. Discharge current in electrical circuit
with a different capacitance of the capacitor
ISSN 1562-6016. ВАНТ. 2021. № 4(134) 175
But current fluctuations have less effect on the emit-
ted energy (see Fig. 2) due to the fact that thermal ra-
diation is determined by the current size and thermody-
namic state of the emitted gas. And thermogasdynamics
processes, under the influence of which there is a
change in the size of the radiation region and the gas
temperature, are more inert than processes in the elec-
tric circuit.
INFLUENCE OF PRESSURE AND GAP
LENGTH ON THERMAL EMISSION
Let’s consider the situation when the parameters of
the energy source do not change, but the parameters of
the load change. Thus, we have unchanged parameters
of the electrical circuit (R, L, C) and unchanged capaci-
tor charge voltage in this case. A change in the load
parameters means a change in the length of the dis-
charge gap and the initial pressure of the working gas.
We assume that a uniform electric field is created in the
discharge gap due to the shape of the electrodes. Then
the dependence of the gap breakdown voltage on the
gap length lsp and the initial gas pressure p0 is repre-
sented by Paschen's law in the form
sp0br lp~U . (8)
Let’s assume that the breakdown of the gas gap oc-
curs under a voltage equal to the voltage of the capaci-
tor charge. Then a fixed voltage of the capacitor charge
in the discharge circuit occurs if the increase in gas
pressure in the discharge gap is compensated by a di-
rectly proportional decrease in the length of the dis-
charge gap, and vice versa.
A numerical study was carried out for an electrical
circuit of the following parameters. The capacitance of
the capacitor was C = 0.05 μF, the resistance of the
discharge circuit was Rc = 0.3 Ω, and the inductance of
the circuit was L = 2 μH. The capacitor charge voltage
was U0 = 30 kV. As a working gas it was considered a
nitrogen at an initial temperature T0 = 300 K. In the
first calculation variant of this study, it was assumed
that the initial gas pressure is p0 = 101.4 kPa, and the
length of the gap is lsp= 10 mm. At the second variant
of the study, it was assumed that the initial gas pressure
is p0 = 202.8 kPa, and the gap length is lsp= 5 mm.
The results of calculating the energy emitted by the
spark discharge at different load parameters are shown
in Fig. 10.
Fig. 10. Time dependence of the energy emitted
by the spark discharge for different spark load
It could be find out from the obtained calculation
results that an increase in the length of the discharge
gap under conditions of a directly proportional decrease
in the working gas pressure leads to a decrease in the
radiated energy. This result shows that a change in the
length of the spark gap affects the change in the radi-
ated energy more intensively than a change in the pres-
sure of the working gas.
According to research presented in the work [6], the
energy deposited into the spark discharge, as a rule, is
directly proportional to the length of the spark gap.
According to the research [16], an increase in the ini-
tial gas pressure in two times at an unchanged initial
gas temperature leads to an increase in the energy de-
posited into the spark discharge by no more than 1.2
times. Hence, when the length of the gap is reduced by
2 times and the gas pressure is increased by 2 times, the
introduced energy decreases by 2/1.17 = 1.71 times.
According to the results of calculations, it was obtained
that for a time of 10 μs at p0= 101.4 kPa and lsp =
10 mm, an energy of 17.76 J is introduced into the
spark channel, where 2.43 J of this energy is consumed
for radiation. And at p0 = 202.8 kPa and lsp = 5 mm for a
time of 10 μs, an energy of 10.06 J is input into the spark
channel, where 1.77 J of this energy is consumed for radia-
tion. Thus, there are changes in the input energy of
17.76/10.06 = 1.76 times. At the same time, in the variants
of the study for a 10 μs (see Fig. 10), we have a change in
the radiated energy 2.43/1.77 = 1.37 times. Such a devia-
tion of the multiplicity of the change in the emitted
energy from the multiplicity of the change in the input
energy is explained by the increase in the share of the
emitted energy under conditions of increasing gas pres-
sure.
In addition to the radiated energy, an important
characteristic of a spark light source is the power of
thermal radiation from a unit surface. The calculation
of the power of thermal radiation was carried out rela-
tive to the surface of the current-conducting channel of
the spark by the expression
dt
dQlrW rad
spchsuf 2 . (9)
The results of calculating the change in radiative
power as function of time for mentioned calculation
projects are shown in Fig. 11.
Fig. 11. The power of thermal radiation
from a unit of surface in calculating variants
It should be mentioned that in the case of an in-
crease in the gas pressure under conditions of a directly
proportional decrease in the gap length, the radiative
power increases for the same discharge time. In par-
ticular, for a time of 1 μs at p0 = 202.8 kPa and lsp = 5
ISSN 1562-6016. ВАНТ. 2021. № 4(134) 176
mm we have Wsuf = 6.805109 W/m2, and at p0 = 101.4
kPa and lsp = 10 mm we have Wsuf = 3.55109 W/m2.
We observe a 1.9-times change in radiative power. This
effect is explained by the fact that although a reduction
in the gap length leads to a decrease in the radiated
energy (see Fig. 10), such a reduction in the length also
leads to a decrease in the radiation surface area.
CONCLUSIONS
It was established that radiative thermal conductiv-
ity together with the gasdynamic process are the main
factors leading to the expansion of the high-
temperature region of the spark channel. It was found
that an increase in the total discharge energy due to
increase in the capacitance does not lead to a directly
proportional increase in the emitted energy at a fixed
time of the spark discharge development. It was estab-
lished that the decrease in instantaneous efficiency of
thermal radiation is caused by a decrease in the effi-
ciency of energy input into the spark discharge. A
change in the gap length affects the change in the radi-
ated energy more intensively than a change in the gas
pressure. It was found out that in the case of an in-
crease in the gas pressure under conditions of a directly
proportional decrease in the gap length, the radiative
power increases for the same discharge time.
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Article received 14.06.2021
ТЕПЛОВОЕ ИЗЛУЧЕНИЕ В ИСКРОВОМ РАЗРЯДЕ
К. Корытченко, Е. Поклонский, Д. Самойленко, Д. Винников, Р. Мелещенко, К. Остапов
Работа посвящена численному исследованию теплового излучения в искровом разряде. Установлено
влияние лучистой теплопроводности на расширение искрового канала. Проведено исследование влияния ве-
личины емкости разрядного конденсатора на энергию, излучаемую разрядом. Рассмотрено изменение тер-
модинамического состояния газа в искровом канале с учетом следующих факторов: изменения емкости раз-
рядного конденсатора, длины разрядного промежутка и начального давления газа. Изучено влияние началь-
ISSN 1562-6016. ВАНТ. 2021. № 4(134) 177
ного давления газа и длины промежутка на параметры теплового излучения газа в условиях постоянного
напряжения пробоя искрового промежутка.
ТЕПЛОВЕ ВИПРОМІНЮВАННЯ В ІСКРОВОМУ РОЗРЯДІ
К. Коритченко, Є. Поклонський, Д. Самойленко, Д. Вінніков, Р. Мелещенко, К. Остапов
Робота присвячена чисельному дослідженню теплового випромінювання в іскровому розряді. Встановле-
но вплив променистої теплопровідності на розширення іскрового каналу. Проведено дослідження впливу
величини ємності розрядного конденсатора на енергію, що випромінюється розрядом. Розглянуто зміну тер-
модинамічного стану газу в іскровому каналі з урахуванням наступних факторів: зміни ємності розрядного
конденсатора, довжини розрядного проміжку і початкового тиску газу. Вивчено вплив початкового тиску
газу і довжини проміжку на параметри теплового випромінювання газу в умовах постійної напруги пробою
іскрового проміжку.
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