Bifurcation behavior in homogeneous-heterogeneous combustion. Part 1. ; Experimental results over platinum

Journal Article · Mon Apr 01 04:00:00 EST 1991 · Combustion and Flame; (United States)

DOI:https://doi.org/10.1016/0010-2180(91)90006-W· OSTI ID:5051462

Williams, W R; Stenzel, M T; Song, X; Schmidt, L D ^[1]

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1. Dept. of Chemical Engineering and Materials Science, Univ. of Minnesota, Minneapolis, MN (US)

Ignition, extinction, and autothermal behavior of the homogeneous and heterogeneous oxidation reactions in air of NH{sub 3}, CH{sub 4}, C{sub 3}H{sub 8}, and an equipolar NH{sub 3}/CH{sub 4} mixture over resistively heated polycrystalline platinum foils was studied in an atmospheric pressure flow reactor as a function of low rate, fuel concentration, preheat temperature, and reactor geometry. Surface temperature versus power curves were experimentally determined for different compositions in these systems, which were in turn summarized in bifurcation diagrams of surface temperature or power as a function of fuel composition. Two ignitions (heterogeneous and homogeneous), one extinction and one self-sustaining autothermal steady state, were observed for all systems except NH{sub 3}/CH{sub 4} oxidation. The heterogeneous ignition occurred around 600 {degrees} C for CH{sub 4} and 200 {degrees} C for all other systems and was weakly dependent on the fuel composition. Long transients due to carbon formation were observed in the autothermal behavior for fuel-rich compositions in the CH{sub 4} system. A second heterogeneous ignition occurred in NH{sub 3}/CH{sub 4} oxidation, which ranged from 400 {degrees} to 600 {degrees} C. Homogeneous reaction ignited at surface temperatures ranging from 1050 {degrees} C for C{sub 3}H{sub 8} oxidation to 1500 {degrees} C for CH{sub 4} and NH{sub 3} oxidation. For C{sub 3}H{sub 8} and CH{sub 4} oxidation, the flame generally left the foil, but in NH {sub 3} oxidation a stable boundary layer flame was also observed under some conditions.

• OSTI ID: 5051462
• Journal Information: Combustion and Flame; (United States), Journal Name: Combustion and Flame; (United States) Vol. 84:CBFMA; ISSN CBFMA; ISSN 0010-2180
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400800* -- Combustion
Pyrolysis
& High-Temperature Chemistry
ALKANES
BEHAVIOR
BOUNDARY LAYERS
CHEMICAL REACTIONS
COMBUSTION
ELEMENTS
FLAMES
FLOW RATE
FOILS
FUELS
HYDROCARBONS
IGNITION
LAYERS
METALS
METHANE
ORGANIC COMPOUNDS
OXIDATION
PLATINUM
PLATINUM METALS
TEMPERATURE EFFECTS
THERMOCHEMICAL PROCESSES
TRANSITION ELEMENTS