THERMAL SCIENCE

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Amir Mardani

,

Sadegh Tabejamaat

NUMERICAL STUDY OF FLAME STRUCTURE IN THE MILD COMBUSTION REGIME

ABSTRACT
In this paper, turbulent non-premixed CH4+H2 jet flame issuing into a hot and diluted co-flow air is studied numerically. This flame is under condition of the moderate or intense low-oxygen dilution (MILD) combustion regime and related to published experimental data. The modelling is carried out using the EDC model to describe turbulence-chemistry interaction. The DRM-22 reduced mechanism and the GRI2.11 full mechanism are used to represent the chemical reactions of H2/methane jet flame. The flame structure for various O2 levels and jet Reynolds numbers are investigated. The results show that the flame entrainment increases by a decrease in O2 concentration at air side or jet Reynolds number. Local extinction is seen in the upstream and close to the fuel injection nozzle at the shear layer. It leads to the higher flame entertainment in MILD regime. The turbulence kinetic energy decay at centre line of jet decreases by an increase in O2 concentration at hot Co-flow. Also, increase in jet Reynolds or O2 level increases the mixing rate and rate of reactions.
KEYWORDS
mild combustion, flame structure, turbulent non-premixed combustion, dilution, preheat
PAPER SUBMITTED: 2012-05-22
PAPER REVISED: 2013-04-09
PAPER ACCEPTED: 2013-06-09
PUBLISHED ONLINE: 2013-07-06
DOI REFERENCE: https://doi.org/10.2298/TSCI120522091M
CITATION EXPORT: view in browser or download as text file
THERMAL SCIENCE YEAR 2015, VOLUME 19, ISSUE Issue 1, PAGES [21 - 34]
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Numerical study of flame structure in the mild combustion regime

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