A numerical study on extinction and NOx formation in nonpremixed flames with syngas fuel

Kangwoo Chun, Hun J. Chung, Suk Ho Chung, Jaehyuk Choi

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12 Scopus citations


The flame structure, extinction, and NOx emission characteristics of syngas/air nonpremixed flames, have been investigated numerically. The extinction stretch rate increased with the increase in the hydrogen proportion in the syngas and with lower fuel dilution and higher initial temperature. It also increased with pressure, except for the case of highly diluted fuel at high pressure. The maximum temperature and the emission index of nitric oxides (EINOx) also increased in aforementioned conditions. The EINOx decreased with stretch rate in general, while the decreasing rate was found to be somewhat different between the cases of N2 and CO2 dilutions. The reaction paths of NOx formation were analyzed and represented as NO reaction path diagram. The increase in N radical resulted in larger NOx production at high initial temperature and pressure. As the pressure increases, EINOx increases slower due to the third-body recombination. The thermal NO mechanism is weakened for high dilution cases and non-thermal mechanisms prevail. The combustion conditions achieving higher extinction stretch rate can be lead to more NOx emission, therefore that the selection of optimum operation range is needed in syngas combustion. © 2011 The Korean Society of Mechanical Engineers and Springer-Verlag Berlin Heidelberg.
Original languageEnglish (US)
Pages (from-to)2943-2949
Number of pages7
JournalJournal of Mechanical Science and Technology
Issue number11
StatePublished - Nov 20 2011

Bibliographical note

KAUST Repository Item: Exported on 2020-10-01

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering


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