Computed Structure of Low Strain Rate Partially Premixed CH4/Air Counterflow Flames: Implications for NO Formation.
Computed Structure of Low Strain Rate Partially Premixed
CH4/Air Counterflow Flames: Implications for NO
Blevins, L. G.; Gore, J. P.
Combustion and Flame, Vol. 116, 546-566, 1999.
Sponsor:Naval Research Lab., Washington, DC
combustion chemistry; computation; counterflow flames;
flame structure; nitrogen oxides; pollution; simulation
Results from computations of low strain rate, partially
premixed methane/air counterflow flames are reported.
The Oppdif computer code was used with GRI-Mech 2.11 to
obtain the results. When the fuel-side equivalence ratio
is above 2.5, the present flame structure can be
described as a CH4/air premixed flame merged with a
CO/H2/air nonpremixed flame. When the equivalence ratio
is below 2.5, the two flame zones exist on the opposite
sides of the stagnation plane, and the CO/H2/air
nonpremixed flame is characterized by hydrocarbon
concentration peaks on its fuel-side edge. Broad NO
destruction regions, caused by CHi+NO reactions, exist
between the result in double hydrocarbon concentration
peaks. The fuel-side equivalence ratio is the most
important indicator of how rapidly NO is destroyed
relative to how rapidly it is formed, and NO destruction
reactions are more important inpure diffusion flames
than in partially premixed flames for the present low
strain rate computations.