Numerical study on NO emission with flue gas dilution in air and fuel sides

Eun Seong Cho, Suk Ho Chung*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


Flue gas recirculation (FGR) is widely adopted to control NO emission in combustion systems. Recirculated flue gas decreases flame temperature and reaction rate, resulting in the decrease in thermal NO production. Recently, it has been demonstrated that the recirculated flue gas in fuel stream, that is, the fuel induced recirculation (FIR), could enhance much improved reduction in NO per unit mass of recirculated gas, as compared to conventional FGR in air. In the present study, the effect of dilution methods in air and fuel sides on NO reduction has been investigated numerically by using N2 and CO 2 as diluent gases to simulate flue gases. Counterflow diffusion flames were studied in conjunction with the laminar flamelet model of turbulent flames. Results showed that CO2 dilution was more effective in NO reduction because of large temperature drop due to the larger specific heat of CO2 compared to N2. Fuel dilution was more effective in reducing NO emission than air dilution when the same recirculation ratio of dilution gas was used by the increase in the nozzle exit velocity, thereby the stretch rate, with dilution gas added to fuel side.

Original languageEnglish (US)
Pages (from-to)1358-1365
Number of pages8
JournalJournal of Mechanical Science and Technology
Issue number6
StatePublished - Jun 2005
Externally publishedYes


  • Counterflow
  • Flue Gas Recirculation (FGR)
  • Fuel Induced Recirculation (FIR)
  • Nitric Oxides

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering


Dive into the research topics of 'Numerical study on NO emission with flue gas dilution in air and fuel sides'. Together they form a unique fingerprint.

Cite this