Title

Effects of fuel Lewis number on and Damkohler number scaling of nitric oxide emission level of Burke-Schumann type flames

Authors

Authors

R. H. Chen; J. E. Navedo;L. Chew

Comments

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Abbreviated Journal Title

Combust. Sci. Technol.

Keywords

nitric oxide; Burke-Schumann flame; diffusion flame; Lewis number; Damkohler number; flame length; JET DIFFUSION FLAMES; PREFERENTIAL DIFFUSION; PREDICTION; MODEL; SIZES; Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical

Abstract

Results are reported on the thermo-diffusive effects in laminar diffusion flames. The flames studied are those of the Burke-Schumann type, with the exceptions that the axial velocity is uniform in the inlet instead of having uniform mass flux, and that the fuel Lewis number is not equal to unity. The fuel Lewis number was varied using argon and helium dilution of the fuel. Dramatic Lewis number effects were experimentally observed. In some cases a higher degree dilution may cause the measured flame temperature (radiation corrected) to be higher than that with lesser dilution if increasing dilution reduces the Lewis number. The NOx emission level of the flame follows similar trend, consistent with the diffusive-thermal effects. A scaling analysis of NOx emission recently proposed for turbulent jet diffusion dames was examined for the present flames. It was found that as the Damkohler number decreases the normalized NOx emission increases. This further confirms the super-equilibrium effects for NOx emission previously found in turbulent jet diffusion flames. The fuel Lewis number was not found to qualitatively affect the Damkohler number scaling of NOx emission, nor did it quantitatively correlate the value of the exponent of the Damkohler number.

Journal Title

Combustion Science and Technology

Volume

127

Issue/Number

1-6

Publication Date

1-1-1997

Document Type

Article

Language

English

First Page

293

Last Page

318

WOS Identifier

WOS:A1997YJ66900015

ISSN

0010-2202

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