Study of nanosecond discharges in H-2-air mixtures at
atmospheric pressure for plasma assisted combustion
applications

KOBAYASHI, Sumire, Zdeněk BONAVENTURA, Fabien THOLIN, Nikolay A POPOV and Anne BOURDON. Study of nanosecond discharges in H-2-air mixtures at atmospheric pressure for plasma assisted combustion applications. Plasma Sources Science and Technology. Bristol: IOP Publishing Ltd., vol. 26, No 7, p. nestránkováno, 12 pp. ISSN 0963-0252. doi:10.1088/1361-6595/aa729a. 2017.

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TY  - JOUR
ID  - 1410971
AU  - Kobayashi, Sumire - Bonaventura, Zdeněk - Tholin, Fabien - Popov, Nikolay A - Bourdon, Anne
PY  - 2017
TI  - Study of nanosecond discharges in H-2-air mixtures at atmospheric pressure for plasma assisted combustion applications
JF  - Plasma Sources Science and Technology
VL  - 26
IS  - 7
SP  - nestránkováno
EP  - nestránkováno
PB  - IOP Publishing Ltd.
SN  - 09630252
KW  - nanosecond pulsed discharge at atmospheric pressure
KW  - streamer and nanosecond spark regimes
KW  - fast gas heating processes
KW  - nonequilibrium kinetics of reactive mixtures
UR  - http://iopscience.iop.org/article/10.1088/1361-6595/aa729a/meta
L2  - http://iopscience.iop.org/article/10.1088/1361-6595/aa729a/meta
N2  - This paper presents 2D simulations of nanosecond discharges between two point electrodes for four different H2–air mixtures defined by their equivalence ratios phgr (i.e. $\phi =0$, air, $\phi =0.3$, lean mixture, $\phi =1$, stoichiometric mixture and $\phi =1.5$, rich mixture) at atmospheric pressure and at an initial temperature of 1000 K. In a first step, we have shown that the mixture composition has only a very small influence on the discharge dynamics and structure during the streamer phase and up to the formation of the plasma channel between the two point electrodes in H2–air mixtures with $\phi \in [0,1.5]$. However, as the plasma channel is formed slightly earlier as the equivalence ratio increases, for a given voltage pulse, the duration of the nanosecond spark phase increases as the equivalence ratio increases. As expected, we have shown that excited states of N2 (and in particular N2(A)) and radicals (and in particular O(D), O(P), H and OH) are very efficiently produced during the voltage pulse after the start of the spark phase. After the voltage pulse, and up to 100 ns, the densities of excited states of N2 and of O(D) decrease. Conversely, most of the O(P), H and OH radicals are produced after the voltage pulse due to the dissociative quenching of electronically excited N2. As for radicals, the gas temperature starts increasing after the start of the spark phase. For all studied mixtures, the density of O(P) atoms and the gas temperature reach their maxima after the end of the voltage pulse and the densities of O(P), H and OH radicals and the maximal gas temperature increase as the equivalence ratio increases. We have shown that the production of radicals is the highest on the discharge axis and the distribution of species after the voltage pulse and up to 100 ns has a larger diameter between the electrodes than close to both electrode tips. As for species, the temperature distribution presents two hot spots close to the point electrode tips. The non-uniform distributions of radical densities and gas temperature obtained after the nanosecond voltage pulse provide accurate initial conditions for 2D reactive flow codes to study the combustion ignition on longer timescales and compare with experiments.
ER  -

Basic information
Original name	Study of nanosecond discharges in H-2-air mixtures at atmospheric pressure for plasma assisted combustion applications
Authors	KOBAYASHI, Sumire (392 Japan), Zdeněk BONAVENTURA (203 Czech Republic, guarantor, belonging to the institution), Fabien THOLIN (250 France), Nikolay A POPOV (643 Russian Federation) and Anne BOURDON (250 France).
Edition	Plasma Sources Science and Technology, Bristol, IOP Publishing Ltd. 2017, 0963-0252.

Other information
Original language	English
Type of outcome	Article in a journal
Field of Study	10305 Fluids and plasma physics
Country of publisher	United Kingdom of Great Britain and Northern Ireland
Confidentiality degree	is not subject to a state or trade secret
WWW	URL
Impact factor	Impact factor: 3.939
RIV identification code	RIV/00216224:14310/17:00095569
Organization unit	Faculty of Science
Doi	http://dx.doi.org/10.1088/1361-6595/aa729a
UT WoS	000403652400002
Keywords in English	nanosecond pulsed discharge at atmospheric pressure; streamer and nanosecond spark regimes; fast gas heating processes; nonequilibrium kinetics of reactive mixtures
Tags	NZ, rivok
Changed by	Changed by: Ing. Nicole Zrilić, učo 240776. Changed: 12/4/2018 09:13.

Abstract

This paper presents 2D simulations of nanosecond discharges between two point electrodes for four different H2–air mixtures defined by their equivalence ratios phgr (i.e. $\phi =0$, air, $\phi =0.3$, lean mixture, $\phi =1$, stoichiometric mixture and $\phi =1.5$, rich mixture) at atmospheric pressure and at an initial temperature of 1000 K. In a first step, we have shown that the mixture composition has only a very small influence on the discharge dynamics and structure during the streamer phase and up to the formation of the plasma channel between the two point electrodes in H2–air mixtures with $\phi \in [0,1.5]$. However, as the plasma channel is formed slightly earlier as the equivalence ratio increases, for a given voltage pulse, the duration of the nanosecond spark phase increases as the equivalence ratio increases. As expected, we have shown that excited states of N2 (and in particular N2(A)) and radicals (and in particular O(D), O(P), H and OH) are very efficiently produced during the voltage pulse after the start of the spark phase. After the voltage pulse, and up to 100 ns, the densities of excited states of N2 and of O(D) decrease. Conversely, most of the O(P), H and OH radicals are produced after the voltage pulse due to the dissociative quenching of electronically excited N2. As for radicals, the gas temperature starts increasing after the start of the spark phase. For all studied mixtures, the density of O(P) atoms and the gas temperature reach their maxima after the end of the voltage pulse and the densities of O(P), H and OH radicals and the maximal gas temperature increase as the equivalence ratio increases. We have shown that the production of radicals is the highest on the discharge axis and the distribution of species after the voltage pulse and up to 100 ns has a larger diameter between the electrodes than close to both electrode tips. As for species, the temperature distribution presents two hot spots close to the point electrode tips. The non-uniform distributions of radical densities and gas temperature obtained after the nanosecond voltage pulse provide accurate initial conditions for 2D reactive flow codes to study the combustion ignition on longer timescales and compare with experiments.

Links
GA15-04023S, research and development project	Name: Pokročilý výzkum kinetických procesů ve streamerových výbojích
GA15-04023S, research and development project	Investor: Czech Science Foundation
LO1411, research and development project	Name: Rozvoj centra pro nízkonákladové plazmové a nanotechnologické povrchové úpravy (Acronym: CEPLANT plus)
LO1411, research and development project	Investor: Ministry of Education, Youth and Sports of the CR

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Study of nanosecond discharges in H-2-air mixtures at atmospheric pressure for plasma assisted ...

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