Variation of equivalence ratio and element ratios in low-pressure premixed flames of aliphatic fuels
In previously published work it was found that the element ratios (such as C/O, H/O, H/C) and the equivalence ratio all varied in the flame zone of a low-pressure premixed fuel-rich benzene/oxygen/argon laminar flat flame. These variations were seen from analyses of both the data and detailed kinetic modeling. In the present work, seven additional flames were analyzed in the same manner, including five flames with a single hydrocarbon fuel (methane, acetylene, ethylene, allene, and propene) and two flames with a mixture of fuels (acetylene/allene, hydrogen/allene). All the flames had argon as the diluent, with pressures between 20 and 37.5 Torr, equivalence ratios between 1.6 and 2.5, cold gas velocities between 42 and 126 cm/sec. All of these flames showed variations in the element ratios and equivalence ratios. Furthermore, these variations changed in a consistent pattern with respect to the molecular weight of the fuel. In the flame zone, the percent change in the H/O, C/O and equivalence ratios increased with increasing molecular weight of the fuel, except for the hydrogen/allene flame in which the C/O ratio first increases, then decreases in the flame zone. Also, unlike all the other hydrocarbon flames, the C/O ratio decreases below its inlet value for the methane flame. The H/O and equivalence ratios decrease below their inlet values for the hydrogen/allene flame. These results are explained in terms of differential diffusion effects between the products and the reactants, which increase as the fuel becomes increasingly heavier than the major carbon- and hydrogen-containing products.
- Research Organization:
- Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sandia National Lab. (SNL-CA), Livermore, CA (United States)
- Sponsoring Organization:
- US Department of Energy (US)
- DOE Contract Number:
- AC04-94AL85000
- OSTI ID:
- 755945
- Report Number(s):
- SAND2000-8606C; TRN: AH200021%%106
- Resource Relation:
- Conference: Western Section of the Combustion Institute, Golden, CO (US), 03/14/2000; Other Information: PBD: 14 Mar 2000
- Country of Publication:
- United States
- Language:
- English
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