Investigation of Nitrogen Oxides Reduction Characteristics in Methane Swirl Flames under Varying Oxidizer Compositions

Silvia Kim; Hyungrok Do

doi:10.15231/jksc.2026.31.1.001

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2026 Vol.31, Issue 1 Next Page

Research Article

Investigation of Nitrogen Oxides Reduction Characteristics in Methane Swirl Flames under Varying Oxidizer Compositions 메탄 스월 화염에서 산화제 조성 변화에 따른 질소산화물 저감 특성 연구

31 March 2026. pp. 1-10

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Abstract

Emissions of nitrogen oxides (NOx) from high-temperature combustion remain a major concern because thermal NOx formation increases sharply with temperature. This study proposes a nitrogen-dilution-based oxidizer composition control strategy inspired by membrane air separation, in which the nitrogen fraction is increased and oxygen concentration reduced without burner modification or active control. Experiments were conducted using a premixed methane-air swirl burner at atmospheric pressure under three oxidizer conditions, and NOx emissions were evaluated as EINOx. Flame structure was analyzed using CH^* chemiluminescence imaging with inverse Abel transform to estimate flame volume and residence time. Under constant fuel flow, nitrogen dilution reduced NOx by up to 45% in concentration and 26% in EINOx due to reduced oxygen concentration and lower adiabatic flame temperature. Overall, the results demonstrate the effectiveness of oxidizer composition control as a practical NOx reduction strategy.

Keywords

Membrane separation

Nitrogen dilution

Thermal NOx

Swirl flame

Inverse Abel transform

Residence time

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Information

Publisher :The Korean Society of Combustion
Publisher(Ko) :한국연소학회
Journal Title :Journal of the Korean Society of Combustion
Journal Title(Ko) :한국연소학회지
Volume : 31
No :1
Pages :1-10
Received Date : 2026-02-19
Revised Date : 2026-03-03
Accepted Date : 2026-03-03
DOI :https://doi.org/10.15231/jksc.2026.31.1.001

Journal of the Korean Society of Combustion ISSN:1226-0959(Print) 2466-2089(Online) 한국연소학회지

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