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Journal of Spectroscopy
Volume 2013, Article ID 304717, 7 pages
http://dx.doi.org/10.1155/2013/304717
Research Article

The Chemiluminescence and Structure Properties of Normal/Inverse Diffusion Flames

Key Laboratory of Coal Gasification and Energy Chemical Engineering of Ministry of Education, East China University of Science and Technology, Shanghai 200237, China

Received 28 June 2012; Accepted 25 September 2012

Academic Editor: Masaki Oura

Copyright © 2013 Ting Zhang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The flame emission spectrometry was applied to detect the distribution of excited radicals in two types CH4/O2 coflow jet diffusion flames (normal and inverse diffusion flames). Combining the image analysis along with the spectrometry, the chemiluminescence and structure characteristics of these diffusion flames were investigated. The results show that the inverse diffusion flame (IDF) with relatively high inlet oxygen velocity is composed of two regions: a bright base and a tower on top of the base, which is quite different from the normal diffusion flame (NDF). The flame is divided into two regions along the flame axis based on maximum OH* position (Region I: initial reaction zone; Region II: further oxidation zone). The degree of the further oxidization taking place in Region II is obvious in accordance with OH* distribution, which is the main difference in reaction zone between fuel-rich condition and fuel-lean condition for NDFs. For IDFs, the change of OH* distribution with increasing equivalence O/C ratio () in Region II is not conspicuous. More OH* and CH* are generated in IDFs, due to the inner high-speed O2 flow promoting the mixing of fuel and oxygen to a certain extent.