Title

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

Authors

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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