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Application of emission spectroscopy in plasma-assisted NH3/air combustion using nanosecond pulsed discharge

Sun, Jinguo LU orcid ; Bao, Yupan LU ; Ravelid, Jonas LU ; Nilsson, Sebastian LU ; Konnov, Alexander A. LU and Ehn, Andreas LU (2024) In Combustion and Flame 263.
Abstract

This work investigates the effects of atmospheric-pressure nanosecond (ns) pulsed plasma discharges on NH3/air flames using optical emission spectroscopy (OES). Firstly, spatially-resolved OES in the 200–800 nm range of NH3/air flames with and without discharges are presented to identify the plasma-induced excited species (such as N2* and H*). Then, time-resolved OES with ns timescale resolution are achieved to illustrate the discharge dynamics using a statistical imaging strategy, which is specifically designed to overcome the timing jitter of the discharge. From the time-resolved spectra of excited N2, the first and second emission events in NH3/air flames with a time interval of... (More)

This work investigates the effects of atmospheric-pressure nanosecond (ns) pulsed plasma discharges on NH3/air flames using optical emission spectroscopy (OES). Firstly, spatially-resolved OES in the 200–800 nm range of NH3/air flames with and without discharges are presented to identify the plasma-induced excited species (such as N2* and H*). Then, time-resolved OES with ns timescale resolution are achieved to illustrate the discharge dynamics using a statistical imaging strategy, which is specifically designed to overcome the timing jitter of the discharge. From the time-resolved spectra of excited N2, the first and second emission events in NH3/air flames with a time interval of 80 ns are revealed, and each exhibits a profile with two exponential decays. Furthermore, spatial- and time-resolved rotational and vibrational temperatures are derived from the spectral fitting of N2(C→B) to quantify the thermal effects of ns plasmas, thus revealing the ultrafast and slow gas heating processes. In addition, the electron number density along the flame is obtained from the intense Hα line, which locally reaches up to 1 × 1017 cm−3. Besides, the spatial-resolved Hα line intensity suggests that the flame chemistry does not directly affect, but the discharge dominates the production of the atomic hydrogen. It provides insight into the kinetic effects of ns pulsed discharge on NH3 combustion enhancement.

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author
; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Electron number density, Emission spectroscopy, Nanosecond pulsed plasma discharge, Nitrogen excitation, Premixed ammonia/air flame
in
Combustion and Flame
volume
263
article number
113400
publisher
Elsevier
external identifiers
  • scopus:85188654045
ISSN
0010-2180
DOI
10.1016/j.combustflame.2024.113400
language
English
LU publication?
yes
id
0163d357-d0bb-4067-8974-934cd637e3ac
date added to LUP
2024-04-22 13:35:00
date last changed
2024-04-22 13:36:14
@article{0163d357-d0bb-4067-8974-934cd637e3ac,
  abstract     = {{<p>This work investigates the effects of atmospheric-pressure nanosecond (ns) pulsed plasma discharges on NH<sub>3</sub>/air flames using optical emission spectroscopy (OES). Firstly, spatially-resolved OES in the 200–800 nm range of NH<sub>3</sub>/air flames with and without discharges are presented to identify the plasma-induced excited species (such as N<sub>2</sub>* and H*). Then, time-resolved OES with ns timescale resolution are achieved to illustrate the discharge dynamics using a statistical imaging strategy, which is specifically designed to overcome the timing jitter of the discharge. From the time-resolved spectra of excited N<sub>2</sub>, the first and second emission events in NH<sub>3</sub>/air flames with a time interval of 80 ns are revealed, and each exhibits a profile with two exponential decays. Furthermore, spatial- and time-resolved rotational and vibrational temperatures are derived from the spectral fitting of N<sub>2</sub>(C→B) to quantify the thermal effects of ns plasmas, thus revealing the ultrafast and slow gas heating processes. In addition, the electron number density along the flame is obtained from the intense H<sub>α</sub> line, which locally reaches up to 1 × 10<sup>17</sup> cm<sup>−3</sup>. Besides, the spatial-resolved H<sub>α</sub> line intensity suggests that the flame chemistry does not directly affect, but the discharge dominates the production of the atomic hydrogen. It provides insight into the kinetic effects of ns pulsed discharge on NH<sub>3</sub> combustion enhancement.</p>}},
  author       = {{Sun, Jinguo and Bao, Yupan and Ravelid, Jonas and Nilsson, Sebastian and Konnov, Alexander A. and Ehn, Andreas}},
  issn         = {{0010-2180}},
  keywords     = {{Electron number density; Emission spectroscopy; Nanosecond pulsed plasma discharge; Nitrogen excitation; Premixed ammonia/air flame}},
  language     = {{eng}},
  publisher    = {{Elsevier}},
  series       = {{Combustion and Flame}},
  title        = {{Application of emission spectroscopy in plasma-assisted NH<sub>3</sub>/air combustion using nanosecond pulsed discharge}},
  url          = {{http://dx.doi.org/10.1016/j.combustflame.2024.113400}},
  doi          = {{10.1016/j.combustflame.2024.113400}},
  volume       = {{263}},
  year         = {{2024}},
}