• Prediction of Combustion and NOx Emission Characteristics of Flameless Oxidation combustion

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This week a paper regarding modelling of flameless oxidation have been published in the IFRF Combustion Journal (http://www.journal.ifrf.net) entitled:

Prediction of Combustion and NOx Emission Characteristics of Flameless Oxidation Combustionby:

I.O. Awosope and F.C. Lockwood

This paper presents the results of mathematical modelling of flameless oxidation (FO), also referred to, in the literature, as high temperature air combustion (HTAC). Of particular interest in this paper is the modelling of the formation of NOx in such a flame. The FO or HTAC burners have gained significant interest in the industrial community recently because of their even heat distribution, high efficiency and low NOx emissions. The authors compare the model results with measured values for temperature and species concentration, including NOx, from three different published experiments. Various radiation and combustion models are compared.


Prof. Fred C. Lockwood
Department of Mechanical Engineering,
Imperial College London,
Exhibition Road,
London SW7 2BX,
United Kingdom

Tel.: 44 207 594 7032
Fax.: 44 207 581 5495
E-mail: f.lockwood@imperial.ac.uk


Flameless oxidation (FO) is proving to be an effective method for the reduction of thermal nitrogen oxides (NOx) emissions and for improving combustion efficiency in high temperature thermal processes. The mathematical modelling of this combustion concept and its application to industry combustor design and analysis is scarce. This paper reports a straightforward combustion model that enables the prediction of the general combustion and NOx pollutant characteristics of the partially premixed and diffusion flame conditions pertaining to FO, which can be conveniently deployed in a computational fluid dynamics (CFD) technique. The methodology is successfully validated against three experimental studies. It is found that an extinction criterion is necessary for good simulation of the ‘classical’ FO condition where the separated fuel and oxidant combustor entry streams have high momenta.  Where a pre-combustor is deployed, allowing FO to be achieved at lower injection momenta, a simple global reaction serves. Radiative losses from the reaction zone are larger than for conventional flames because of the high recirculation ratio of high emissivity product gases. These losses significantly reduce the combustion temperature and so the NOx.

Key words: Flameless Oxidation, Turbulent Combustion and High Temperature Air Combustion Application


The full paper may be downloaded from the server, in the “New Papers” section (http://www.journal.ifrf.net/articles.html), by clicking on the Acrobat PDF icon alongside the title.

Publication in the Journal

The Editor-in-Chief (See associated article in this edition of the MNM) would like to remind all potential authors that publication in the Journal is open to all. If you have interesting results to publish in the field of, or related to, industrial combustion, we invite you to prepare a paper according to the guidelines given in the Author’s Guide on the website


Papers may be regular “articles” (typically up to 20 pages) or Communications (typically up to 4/5 pages). Review papers can of course be longer. Remember that figures and graphics in general can be in full colour. This advantage should be encouraged.

All manuscripts and associated files, proposed for publication should be sent by the Corresponding Author in a compressed/zip file, as an email attachment to journal@ifrf.net. This file should include a statement that the proposal’s content is unpublished material that has not being submitted for publication elsewhere. When an article by the author(s) is cited in the proposed article as “in press”, a copy of this article should accompany the proposed article and should be included in the compressed file.

The Editor-in-Chief looks forward to receiving your proposals.