The influence of catalytic activity on the ignition of boundary layer flows. Part 3; Hydroxyl radical measurements in low-pressure boundary layer flows
- Yale Univ., Dept. of Chemical Engineering, New Haven, CT (US)
- SRI International, Molecular Physics Dept., Menlo Park, CA (US)
In this paper, the boundary layer ignition of fuel/air mixture by heated catalytic (platinum) and noncatalytic (quartz) surfaces was studied through spatially resolved measurement of hydroxyl radicals at total pressures from 40 to 175 torr. Fuels studied include ethane, acetylene, hydrogen, and methane, usually premixed in air. Ethane ignition was promoted by catalytic reaction at all equivalence ratios studied. This was a wider range of equivalence ratios evidencing catalytic enhancement than noted at atmospheric pressure in previous studied. At 70 torr, this enhancement was observed from 0.015 {lt} {phi} {le} 0.5. Surface hydroxyl radical production rates were estimated for preignition conditions in the gas phase for ethane in air over both quartz and platinum surfaces. Combustion of hydrogen or acetylene in air at these conditions was not significantly affected by the catalytic activity of the surface, because for the reactions studied, gas-phase reaction was significant near the leading edge of the plate. N{sub 2}O substitution for O{sub 2} severely inhibited the gaseous ignition of the ethane, hydrogen, and acetylene over platinum surfaces, and suppressed preignition OH concentrations to below our detection limits.
- OSTI ID:
- 7271790
- Journal Information:
- Combustion and Flame; (United States), Vol. 90:1; ISSN 0010-2180
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ACETYLENE
IGNITION
AIR
FUELS
HYDROGEN
HYDROXYL RADICALS
PRODUCTION
METHANE
BOUNDARY LAYERS
CATALYSIS
ETHANE
FLUID FLOW
FUEL-AIR RATIO
HEATING
MIXTURES
NITROUS OXIDE
PLATINUM
QUARTZ
SPATIAL RESOLUTION
SURFACES
ALKANES
ALKYNES
CHALCOGENIDES
DISPERSIONS
ELEMENTS
FLUIDS
GASES
HYDROCARBONS
LAYERS
METALS
MINERALS
NITROGEN COMPOUNDS
NITROGEN OXIDES
NONMETALS
ORGANIC COMPOUNDS
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PLATINUM METALS
RADICALS
RESOLUTION
TRANSITION ELEMENTS
400800* - Combustion
Pyrolysis
& High-Temperature Chemistry