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

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216224%3A14310%2F17%3A00095569" target="_blank" >RIV/00216224:14310/17:00095569 - isvavai.cz</a>

Result on the web

<a href="http://iopscience.iop.org/article/10.1088/1361-6595/aa729a/meta" target="_blank" >http://iopscience.iop.org/article/10.1088/1361-6595/aa729a/meta</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1088/1361-6595/aa729a" target="_blank" >10.1088/1361-6595/aa729a</a>

Result language

angličtina

Original language name

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

Original language description

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.

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

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OECD FORD branch

10305 - Fluids and plasma physics (including surface physics)

Project

Result was created during the realization of more than one project. More information in the Projects tab.

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2017

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Plasma Sources Science and Technology

ISSN

0963-0252

e-ISSN

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Volume of the periodical

26

Issue of the periodical within the volume

7

Country of publishing house

GB - UNITED KINGDOM

Number of pages

12

Pages from-to

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UT code for WoS article

000403652400002

EID of the result in the Scopus database

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