Nitric oxide formation and carbon monoxide decay in the post-reaction zone of a premixed propane — air flat burner flame
✍ Scribed by Toshimi Takagi; Kenichi Fujii; Mitsunobu Ogasawara
- Publisher
- Elsevier Science
- Year
- 1973
- Tongue
- English
- Weight
- 649 KB
- Volume
- 52
- Category
- Article
- ISSN
- 0016-2361
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✦ Synopsis
Concentrations of he combustion products, especially carbon monoxide and nitric oxide, from a propane-air premixed flat burner flame were measured along the gas stream beyond the flame, and the results were examined in conjunction with chemical-kinetic calculations. It was concluded that the formation and stabilizing (with fall of temperature) of nitric oxide in stoichiometric or fuel-lean flames can be predicted by two reactions, 0 + N2 = NO + N and N + 02 = NO + 0, and that the relative discrepancy between kinetic and simplified-partial-equilibrium models near the flame decreases downstream. For fuel-rich flames, very rapid nitric oxide formation was observed in the reaction zone; this cannot readily be explained by the above reactions in the post-reaction zone even if oxygen-atom 'overshoot' is taken into account. For example, at equivalence ratio # = 1.4, the necessary oxygen-atom concentration in the reaction zone would be more than 3000 times the chemical equilibrium concentration. Some reactions other than the above may need to be taken into account. The excess concentration of carbon monoxide observed just beyond the fuel-lean flame disappears rapidly along the gas flow, within about 3 ms. Its decay rate is considered to be dependent on a recombination reaction, H + OH + M = H$ + M, while the conversion reaction, CO + OH = CO2 + H, is so rapid that it can be presumed to be in partial equilibrium immediately after the flame.