NO formation analysis of turbulent non-premixed coaxial methane/air diffusion flame

S. Poozesh, N. Akafuah, K. Saito

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


Natural gas combustion is one of the primary sources of harvesting energy for various processes and has gained a wide attention during the past decade. One of the most recent applications of natural gas combustion can be found in non-premixed combustion of methane in a coflow burner system. One of the main environmental concerns that arises from the natural gas combustion is the formation of NO produced by thermal NO and prompt NO mechanisms. Current paper is devoted on an examination of a 2D numerical simulation of turbulent non-premixed coaxial methane combustion in air enclosed by an axisymmetric cylindrical chamber to study the effects of species concentrations of reactants on NO formation, their individual contributions, and the chamber outlet temperature. A finite-volume staggered grid method is utilized to solve conservation equations of mass, energy, momentum, and species concentrations. In order to handle radiation heat transfer, discrete transfer method is used to solve radiation equation. Utilizing weighted-sum-of-gray-gases model, based on the newly obtained high-temperature molecular spectroscopic data, local variations of species absorption coefficients are taken into account. To calculate NO concentration, a single- or joint-variable probability density function in terms of a normalized temperature, mass fractions of species, or a combination of both is employed. Plus, published relevant experimental data are used to validate temperature and species concentration fields. It is shown that a decrease in N2 concentration contributes to reducing NO. More importantly for higher O2 mass fraction, thermal NO formation becomes the dominant mechanism responsible for NO emission.

Original languageEnglish
Pages (from-to)513-518
Number of pages6
JournalInternational Journal of Environmental Science and Technology
Issue number2
StatePublished - Feb 1 2016

Bibliographical note

Funding Information:
This work was supported by IR4TD in Lexington, Kentucky.

Publisher Copyright:
© 2015, Islamic Azad University (IAU).


  • Finite-volume method
  • High-temperature molecular spectroscopic database
  • Natural gas combustion
  • NO environmental pollution
  • Turbulent flame

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • General Agricultural and Biological Sciences


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