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

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Over-rich combustion of CH4, C2H6, and C3H8 +air premixed flames investigated by the heat flux method and kinetic modeling. / Han, Xinlu; Wang, Zhihua; He, Yong; Wang, Shixing; Zhu, Yanqun; Konnov, Alexander A.

I: Combustion and Flame, Vol. 210, 2019, s. 339-349.

Forskningsoutput: TidskriftsbidragArtikel i vetenskaplig tidskrift

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T1 - Over-rich combustion of CH4, C2H6, and C3H8 +air premixed flames investigated by the heat flux method and kinetic modeling

AU - Han, Xinlu

AU - Wang, Zhihua

AU - He, Yong

AU - Wang, Shixing

AU - Zhu, Yanqun

AU - Konnov, Alexander A.

PY - 2019

Y1 - 2019

N2 - 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.

AB - 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.

KW - Laminar burning velocity

KW - Over-rich regime

KW - Super adiabatic flame temperature

KW - Temperature dependence

U2 - 10.1016/j.combustflame.2019.09.009

DO - 10.1016/j.combustflame.2019.09.009

M3 - Article

AN - SCOPUS:85072249367

VL - 210

SP - 339

EP - 349

JO - Combustion and Flame

JF - Combustion and Flame

SN - 0010-2180

ER -