Flame propagation enhancement by plasma excitation of oxygen. Part I: Effects of O{sub 3}

Journal Article · Fri Oct 15 00:00:00 EDT 2010 · Combustion and Flame

DOI:https://doi.org/10.1016/J.COMBUSTFLAME.2010.02.005· OSTI ID:21350368

Ombrello, Timothy; Won, Sang Hee; Ju, Yiguang ^[1]; Williams, Skip ^[2]

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1. Department of Mechanical and Aerospace Engineering, Engineering Quadrangle, Olden Street, Princeton, NJ 08544 (United States)
2. Air Force Research Laboratory, Propulsion Directorate, 1950 Fifth Street, Wright-Patterson AFB, OH 45433 (United States)

The thermal and kinetic effects of O{sub 3} on flame propagation were investigated experimentally and numerically by using C{sub 3}H{sub 8}/O{sub 2}/N{sub 2} laminar lifted flames. Ozone produced by a dielectric barrier plasma discharge was isolated and measured quantitatively by using absorption spectroscopy. Significant kinetic enhancement by O{sub 3} was observed by comparing flame stabilization locations with and without O{sub 3} production. Experiments at atmospheric pressures showed an 8% enhancement in the flame propagation speed for 1260 ppm of O{sub 3} addition to the O{sub 2}/N{sub 2} oxidizer. Numerical simulations showed that the O{sub 3} decomposition and reaction with H early in the pre-heat zone of the flame produced O and OH, respectively, from which the O reacted rapidly with C{sub 3}H{sub 8} and produced additional OH. The subsequent reaction of OH with the fuel and fuel fragments, such as CH{sub 2}O, provided chemical heat release at lower temperatures to enhance the flame propagation speed. It was shown that the kinetic effect on flame propagation enhancement by O{sub 3} reaching the pre-heat zone of the flame for early oxidation of fuel was much greater than that by the thermal effect from the energy contained within O{sub 3}. For non-premixed laminar lifted flames, the kinetic enhancement by O{sub 3} also induced changes to the hydrodynamics at the flame front which provided additional enhancement of the flame propagation speed. The present results will have a direct impact on the development of detailed plasma-flame kinetic mechanisms and provided a foundation for the study of combustion enhancement by O{sub 2}(a{sup 1}{delta}{sub g}) in part II of this investigation. (author)

• OSTI ID: 21350368
• Journal Information: Combustion and Flame, Vol. 157, Issue 10; Other Information: Elsevier Ltd. All rights reserved; ISSN 0010-2180
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
COMBUSTION
FLAME PROPAGATION
OZONE
LAMINAR FLAMES
PROPANE
HEAT
VELOCITY
EXCITATION
FORMALDEHYDE
NITROGEN
FUELS
HYDRODYNAMICS
COMPUTERIZED SIMULATION
HYDROGEN
COMBUSTION KINETICS
OXYGEN
PLASMA
DECOMPOSITION
ZONES
ATMOSPHERIC PRESSURE
TEMPERATURE DEPENDENCE
STABILIZATION
AUGMENTATION
Plasma-assisted combustion
Lifted flames
Tribrachial flames