Fluorescence lifetime imaging of nitric oxide in nanosecond pulsed discharge-assisted NH3/air flames
Sun, Jinguo LU
; Nilsson, Sebastian
LU
; Ravelid, Jonas
LU
; Bao, Yupan
LU
and Ehn, Andreas
LU
(2025)
In Plasma Sources Science and Technology
- Abstract
- Laser-induced fluorescence (LIF) is a widely used non-invasive method for characterizing NOx emission, mostly in combustion applications, but also in many plasma facilities. Under the carbon-free prerequisite, non-thermal plasma-assisted combustion (PAC) is a promising technology to address the low flammability issues of ammonia (NH3) flames, but nitric oxide (NO) emission remains unknown. NO quantification in such plasma-flame environments is a daunting task due to largely unknown fluorescence quenching, which urgently drives this study. In this work, we map the NO fluorescence lifetime (τ) in an NH3/air flame sustained in a nanosecond pulsed discharge (NPD) at various time delays. Firstly, in both burnt and unburnt zones, τ increases... (More)
- Laser-induced fluorescence (LIF) is a widely used non-invasive method for characterizing NOx emission, mostly in combustion applications, but also in many plasma facilities. Under the carbon-free prerequisite, non-thermal plasma-assisted combustion (PAC) is a promising technology to address the low flammability issues of ammonia (NH3) flames, but nitric oxide (NO) emission remains unknown. NO quantification in such plasma-flame environments is a daunting task due to largely unknown fluorescence quenching, which urgently drives this study. In this work, we map the NO fluorescence lifetime (τ) in an NH3/air flame sustained in a nanosecond pulsed discharge (NPD) at various time delays. Firstly, in both burnt and unburnt zones, τ increases slightly in the first 2 μs after the discharge, and then almost remains constant. Secondly, the impact of NPD on τ differs between the burnt and unburnt zones. In the burnt zone, τ of NO exhibits a modest increase (less than 10%) compared to that without NPD pulses, which can be theoretically explained by the temperature rise (i.e., decreased number density) due to the NPD pulse. Besides, a shock front originates from the anode in the burnt zone and exhibits a dip in τ. This further supports the decisive role of number density in quenching of laser-excited NO(A). However, in the unburnt zone, where plasma-induced NO is primarily generated, within the measured 1–100 μs delay after the discharge, τ is unexpectedly long, twice that of the theoretical calculation. It might be attributed to the plasma-induced NH3 decomposition and other excited radicals at low temperatures. These experimental findings clarify, for the first time, the impact of non-thermal NPD on NO(A) quenching, providing a foundation for quantitative analysis of NO in plasma applications. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/efd102ce-be25-439d-9086-fee83533d7b1
- author
- Sun, Jinguo
LU
; Nilsson, Sebastian
LU
; Ravelid, Jonas
LU
; Bao, Yupan
LU
and Ehn, Andreas
LU
- organization
- publishing date
- 2025
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Plasma Sources Science and Technology
- publisher
- IOP Publishing
- external identifiers
-
- scopus:105000364044
- ISSN
- 0963-0252
- language
- English
- LU publication?
- yes
- id
- efd102ce-be25-439d-9086-fee83533d7b1
- alternative location
- http://iopscience.iop.org/article/10.1088/1361-6595/adbd70
- date added to LUP
- 2025-03-08 10:19:26
- date last changed
- 2025-05-16 04:01:30
@article{efd102ce-be25-439d-9086-fee83533d7b1,
abstract = {{Laser-induced fluorescence (LIF) is a widely used non-invasive method for characterizing NOx emission, mostly in combustion applications, but also in many plasma facilities. Under the carbon-free prerequisite, non-thermal plasma-assisted combustion (PAC) is a promising technology to address the low flammability issues of ammonia (NH3) flames, but nitric oxide (NO) emission remains unknown. NO quantification in such plasma-flame environments is a daunting task due to largely unknown fluorescence quenching, which urgently drives this study. In this work, we map the NO fluorescence lifetime (τ) in an NH3/air flame sustained in a nanosecond pulsed discharge (NPD) at various time delays. Firstly, in both burnt and unburnt zones, τ increases slightly in the first 2 μs after the discharge, and then almost remains constant. Secondly, the impact of NPD on τ differs between the burnt and unburnt zones. In the burnt zone, τ of NO exhibits a modest increase (less than 10%) compared to that without NPD pulses, which can be theoretically explained by the temperature rise (i.e., decreased number density) due to the NPD pulse. Besides, a shock front originates from the anode in the burnt zone and exhibits a dip in τ. This further supports the decisive role of number density in quenching of laser-excited NO(A). However, in the unburnt zone, where plasma-induced NO is primarily generated, within the measured 1–100 μs delay after the discharge, τ is unexpectedly long, twice that of the theoretical calculation. It might be attributed to the plasma-induced NH3 decomposition and other excited radicals at low temperatures. These experimental findings clarify, for the first time, the impact of non-thermal NPD on NO(A) quenching, providing a foundation for quantitative analysis of NO in plasma applications.}},
author = {{Sun, Jinguo and Nilsson, Sebastian and Ravelid, Jonas and Bao, Yupan and Ehn, Andreas}},
issn = {{0963-0252}},
language = {{eng}},
publisher = {{IOP Publishing}},
series = {{Plasma Sources Science and Technology}},
title = {{Fluorescence lifetime imaging of nitric oxide in nanosecond pulsed discharge-assisted NH3/air flames}},
url = {{http://iopscience.iop.org/article/10.1088/1361-6595/adbd70}},
year = {{2025}},
}