Advanced

Over-rich combustion of CH4, C2H6, and C3H8 +air premixed flames investigated by the heat flux method and kinetic modeling

Han, Xinlu LU ; Wang, Zhihua ; He, Yong ; Wang, Shixing ; Zhu, Yanqun and Konnov, Alexander A. LU (2019) In Combustion and Flame 210. p.339-349
Abstract

An uncommon non-monotonic behavior of the temperature dependence of adiabatic laminar burning velocity has been found in over-rich methane+air flames at equivalence ratio, ϕ = 1.4. To find out the universality and reasons of this turning point, methane, ethane and propane + air flames are studied both experimentally by the heat flux method and numerically using GRI-mech, USC-mech, UCSD-mech, FFCM mech, and Aramco mech over ϕ = 0.6–1.8, at unburned temperatures up to 368 K, and atmospheric pressure. Results show that the over-rich phenomena stem from a unique flame structure, where, after the flame front, H2O is reduced to H2 and C2Hx (x>1) is oxidized to CO, causing the temperature overtone... (More)

An uncommon non-monotonic behavior of the temperature dependence of adiabatic laminar burning velocity has been found in over-rich methane+air flames at equivalence ratio, ϕ = 1.4. To find out the universality and reasons of this turning point, methane, ethane and propane + air flames are studied both experimentally by the heat flux method and numerically using GRI-mech, USC-mech, UCSD-mech, FFCM mech, and Aramco mech over ϕ = 0.6–1.8, at unburned temperatures up to 368 K, and atmospheric pressure. Results show that the over-rich phenomena stem from a unique flame structure, where, after the flame front, H2O is reduced to H2 and C2Hx (x>1) is oxidized to CO, causing the temperature overtone (super adiabatic flame temperature), while some key reactions important for flame propagation changing their sensitivity signs. Inside the flame front, the importance of CH3 overwhelms other radicals like OH and H. By these distinguishing features, a method using temperature overtone to identify accurate turning points of over-rich regime is demonstrated.

(Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Laminar burning velocity, Over-rich regime, Super adiabatic flame temperature, Temperature dependence
in
Combustion and Flame
volume
210
pages
11 pages
publisher
Elsevier
external identifiers
  • scopus:85072249367
ISSN
0010-2180
DOI
10.1016/j.combustflame.2019.09.009
language
English
LU publication?
yes
id
11ea5d1d-2e5f-408e-9716-0100a5317a09
date added to LUP
2019-09-27 14:16:41
date last changed
2020-01-13 02:25:22
@article{11ea5d1d-2e5f-408e-9716-0100a5317a09,
  abstract     = {<p>An uncommon non-monotonic behavior of the temperature dependence of adiabatic laminar burning velocity has been found in over-rich methane+air flames at equivalence ratio, ϕ = 1.4. To find out the universality and reasons of this turning point, methane, ethane and propane + air flames are studied both experimentally by the heat flux method and numerically using GRI-mech, USC-mech, UCSD-mech, FFCM mech, and Aramco mech over ϕ = 0.6–1.8, at unburned temperatures up to 368 K, and atmospheric pressure. Results show that the over-rich phenomena stem from a unique flame structure, where, after the flame front, H<sub>2</sub>O is reduced to H<sub>2</sub> and C<sub>2</sub>H<sub>x</sub> (x&gt;1) is oxidized to CO, causing the temperature overtone (super adiabatic flame temperature), while some key reactions important for flame propagation changing their sensitivity signs. Inside the flame front, the importance of CH<sub>3</sub> overwhelms other radicals like OH and H. By these distinguishing features, a method using temperature overtone to identify accurate turning points of over-rich regime is demonstrated.</p>},
  author       = {Han, Xinlu and Wang, Zhihua and He, Yong and Wang, Shixing and Zhu, Yanqun and Konnov, Alexander A.},
  issn         = {0010-2180},
  language     = {eng},
  pages        = {339--349},
  publisher    = {Elsevier},
  series       = {Combustion and Flame},
  title        = {Over-rich combustion of CH<sub>4</sub>, C<sub>2</sub>H<sub>6</sub>, and C<sub>3</sub>H<sub>8</sub> +air premixed flames investigated by the heat flux method and kinetic modeling},
  url          = {http://dx.doi.org/10.1016/j.combustflame.2019.09.009},
  doi          = {10.1016/j.combustflame.2019.09.009},
  volume       = {210},
  year         = {2019},
}