Use of laser-induced spark for studying ignition stability and unburned hydrogen escaping from laminar diluted hydrogen diffusion jet flames

    Authors

    T. X. Phuoc;R. H. Chen

    Comments

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    Abbreviated Journal Title

    Opt. Lasers Eng.

    Keywords

    diluted diffusion flame; hydrogen; unburned hydrogen; laser ignition; ignition liftoff; flame stabilization; LIBS; FUEL LEWIS NUMBER; TO-AIR RATIO; NONPREMIXED JET; NITRIC-OXIDE; INSTABILITY; EXTINCTION; CHEMISTRY; MIXTURE; Optics

    Abstract

    Ignition and unburned hydrogen escaping from hydrogen jet diffusion flames diluted with nitrogen up to 70% were experimentally studied. The successful ignition locations were about 2/3 of the flame length above the jet exit for undiluted flames and moved much closer to the exit for diluted flames. For higher levels of dilution or higher flow rates, there existed a region within which a diluted hydrogen diffusion flame can be ignited and burns with a stable liftoff height. This is contrary to previous findings that pure and diluted hydrogen jet diffusion cannot achieve a stable lifted flame configuration. With liftoff, the flame is noisy and short with significant amount of unburned hydrogen escaping into the product gases. If ignition is initiated below this region, the flame propagates upstream quickly and attaches to the burner rim. Results from measurements of unburned hydrogen in the combustion products showed that the amount of unburned hydrogen increased as the nitrogen dilution level was increased. Thus, hydrogen diffusion flame diluted with nitrogen cannot burn completely. Published by Elsevier Ltd.

    Journal Title

    Optics and Lasers in Engineering

    Volume

    45

    Issue/Number

    8

    Publication Date

    1-1-2007

    Document Type

    Article

    Language

    English

    First Page

    834

    Last Page

    842

    WOS Identifier

    WOS:000247860600002

    ISSN

    0143-8166

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