Effect of Strain Rate on NO Formation Characteristics in One-Dimensional Counterflow Diffusion Flame of CH4/NH3 Fuel With O2/CO2 Oxidizer

초록

This study introduces the effect of strain rate on the NO formation characteristics using simple one-dimensional counterflow diffusion flame model. This study found that NO formation strongly depends on the global strain rate in the counterflow diffusion flame. Depending on the global strain rate, the NO formation either monotonically or nonmonotonically increases with increasing oxygen content in the oxidizer. This is primarily attributed to the increase in the net NO formation rate with increasing strain rate, leading to a narrower flame zone. The overestimation in the GRI-Mech 3.0 mechanism is mainly associated with the NO formation within the HNO pathway, especially with H + HNO <-> H2 + NO, HNO + M <-> H + NO + M, and HNO + OH <-> H2O + NO reactions. The Mendiara-Glarborg and Glarborg 2018 mechanisms conform well with the measured trend regardless of the range of global strain rate, while GRI-Mech 3.0 and Okafor's mechanisms demonstrate reasonably good agreement, except at low strain rate corresponding to laminar flame.

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