The structure of partially premixed methane flames in high-intensity turbulent flows

Journal Article · Mon Sep 15 04:00:00 EDT 2008 · Combustion and Flame

DOI:https://doi.org/10.1016/J.COMBUSTFLAME.2008.05.025· OSTI ID:21116077

Yaldizli, Murat; Mehravaran, Kian; Mohammad, Hyderuddin; Jaberi, Farhad A ^[1]

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1. Department of Mechanical Engineering, Michigan State University, East Lansing, MI 48824 (United States)

Direct numerical simulations (DNS) are conducted to study the structure of partially premixed and non-premixed methane flames in high-intensity two-dimensional isotropic turbulent flows. The results obtained via ''flame normal analysis'' show local extinction and reignition for both non-premixed and partially premixed flames. Dynamical analysis of the flame with a Lagrangian method indicates that the time integrated strain rate characterizes the finite-rate chemistry effects and the flame extinction better than the strain rate. It is observed that the flame behavior is affected by the ''pressure-dilatation'' and ''viscous-dissipation'' in addition to strain rate. Consistent with previous studies, high vorticity values are detected close to the reaction zone, where the vorticity generation by the ''baroclinic torque'' was found to be significant. The influences of (initial) Reynolds and Damkoehler numbers, and various air-fuel premixing levels on flame and turbulence variables are also studied. It is observed that the flame extinction occurs similarly in flames with different fuel-air premixing. Our simulations also indicate that the CO emission increases as the partial premixing of the fuel with air increases. Higher values of the temperature, the OH mass fraction and the CO mass fraction are observed within the flame zone at higher Reynolds numbers. (author)

• OSTI ID: 21116077
• Journal Information: Combustion and Flame, Journal Name: Combustion and Flame Journal Issue: 4 Vol. 154; ISSN CBFMAO; ISSN 0010-2180
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
AIR
CARBON MONOXIDE
CHEMICAL COMPOSITION
CHEMICAL REACTIONS
COMPUTERIZED SIMULATION
EMISSION
FLAME EXTINCTION
FLAMES
IGNITION
ISOTROPY
LAGRANGIAN FUNCTION
METHANE
MIXING
Partially premixed flames
REYNOLDS NUMBER
Reduced chemistry models
STRAIN RATE
TURBULENCE
TURBULENT FLOW
TWO-DIMENSIONAL CALCULATIONS
Turbulent reacting flows
VORTICES