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Characteristics of MILD combustion of CH4-CO2 jets in a piloted burner – Laser-diagnostic and LES studies

Raveesh, Meena LU ; Xu, Leilei LU ; Dominguez, Armand LU ; Ruchkina, Maria LU ; Aldén, Marcus LU ; Bood, Joakim LU ; Brackmann, Christian LU and Bai, Xue Song LU (2025) In Combustion and Flame 273.
Abstract

Fundamental characteristics of the reaction-zone structure for CH4-CO2 jets, mimicking a fuel of high CO2 contents such as biogas, burning in a heated coflow on a piloted jet burner have been investigated. Jet flames under diffusion and MILD combustion conditions were studied using planar laser-induced fluorescence (PLIF) of O-atom radicals and CO for different CO2 contents of the fuel jet. Numerical simulations using detailed chemical kinetics were performed to gain further insights into the problem. The impact of fuel jet CO2 contents and jet velocity have been investigated. The main results include (a) quantification of O-atom radical and CO concentration from PLIF measurements,... (More)

Fundamental characteristics of the reaction-zone structure for CH4-CO2 jets, mimicking a fuel of high CO2 contents such as biogas, burning in a heated coflow on a piloted jet burner have been investigated. Jet flames under diffusion and MILD combustion conditions were studied using planar laser-induced fluorescence (PLIF) of O-atom radicals and CO for different CO2 contents of the fuel jet. Numerical simulations using detailed chemical kinetics were performed to gain further insights into the problem. The impact of fuel jet CO2 contents and jet velocity have been investigated. The main results include (a) quantification of O-atom radical and CO concentration from PLIF measurements, (b) numerical simulations of transition from conventional diffusion flame to MILD combustion, and (c) investigation of criteria for MILD combustion, including (i) peak flame temperature or the difference between peak flame temperature and cross-over temperature, (ii) peak CO and NO concentrations, and (iii) flame chemiluminescence. Numerical results show good agreement with experimental data for trends in CO and O-atom concentrations, shapes of spatial profiles, and quantitative CO concentrations. The PLIF and LES results show that in MILD combustion, concentrations of NO and CO are significantly lower than those in conventional flames. MILD combustion can be achieved in the present flames when the CO2 contents of the jet is 60 % or higher, when the difference between the peak flame temperature and the cross-over temperature is <550 K.

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author
; ; ; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Distributed reactions, Large eddy simulation, Laser-induced fluorescence, Mild combustion, Turbulence/flame interaction
in
Combustion and Flame
volume
273
article number
113955
publisher
Elsevier
external identifiers
  • scopus:85213948203
ISSN
0010-2180
DOI
10.1016/j.combustflame.2024.113955
language
English
LU publication?
yes
id
ecb0ae8d-7b26-4caf-8436-9b77af622ac7
date added to LUP
2025-03-11 14:42:46
date last changed
2025-04-04 15:16:01
@article{ecb0ae8d-7b26-4caf-8436-9b77af622ac7,
  abstract     = {{<p>Fundamental characteristics of the reaction-zone structure for CH<sub>4</sub>-CO<sub>2</sub> jets, mimicking a fuel of high CO<sub>2</sub> contents such as biogas, burning in a heated coflow on a piloted jet burner have been investigated. Jet flames under diffusion and MILD combustion conditions were studied using planar laser-induced fluorescence (PLIF) of O-atom radicals and CO for different CO<sub>2</sub> contents of the fuel jet. Numerical simulations using detailed chemical kinetics were performed to gain further insights into the problem. The impact of fuel jet CO<sub>2</sub> contents and jet velocity have been investigated. The main results include (a) quantification of O-atom radical and CO concentration from PLIF measurements, (b) numerical simulations of transition from conventional diffusion flame to MILD combustion, and (c) investigation of criteria for MILD combustion, including (i) peak flame temperature or the difference between peak flame temperature and cross-over temperature, (ii) peak CO and NO concentrations, and (iii) flame chemiluminescence. Numerical results show good agreement with experimental data for trends in CO and O-atom concentrations, shapes of spatial profiles, and quantitative CO concentrations. The PLIF and LES results show that in MILD combustion, concentrations of NO and CO are significantly lower than those in conventional flames. MILD combustion can be achieved in the present flames when the CO<sub>2</sub> contents of the jet is 60 % or higher, when the difference between the peak flame temperature and the cross-over temperature is &lt;550 K.</p>}},
  author       = {{Raveesh, Meena and Xu, Leilei and Dominguez, Armand and Ruchkina, Maria and Aldén, Marcus and Bood, Joakim and Brackmann, Christian and Bai, Xue Song}},
  issn         = {{0010-2180}},
  keywords     = {{Distributed reactions; Large eddy simulation; Laser-induced fluorescence; Mild combustion; Turbulence/flame interaction}},
  language     = {{eng}},
  publisher    = {{Elsevier}},
  series       = {{Combustion and Flame}},
  title        = {{Characteristics of MILD combustion of CH<sub>4</sub>-CO<sub>2</sub> jets in a piloted burner – Laser-diagnostic and LES studies}},
  url          = {{http://dx.doi.org/10.1016/j.combustflame.2024.113955}},
  doi          = {{10.1016/j.combustflame.2024.113955}},
  volume       = {{273}},
  year         = {{2025}},
}