Experimental Study on the Effect of Swirling Flow and Oxidizer Type on the Stability, Light Emission, and Pollutant Emissions of Non-Premixed Propane Flames

Document Type : Research Paper

Authors
Soroush Sarrafan Sadeghi 1
Sadegh Tabejamaat 1
Alireza Javareshkian 2
1 Department of Aerospace Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran
2 Department of Mechanical Engineering, Technical University of Munich, Munich, Germany
10.22055/jacm.2025.48481.5262
Abstract
This experimental study examines the effects of swirling oxidizer flow and oxidizer type (air vs. oxygen) on non-premixed propane flames in a vane-type swirl burner. Using swirler angles of 30°, 45°, and 60°, we investigated flame stability limits, light emission via a Lux meter, temperature distribution, and pollutant emissions (CO, CxHy, NOx) at varied oxidizer flow rates. Increasing the swirl angle enhances air flame stability, expanding the stable operating range against lift-off. Oxygen flames exhibited exceptional stability, with no instabilities observed within the tested range. Light emission, measured by a Lux meter, correlated positively with temperature and was significantly higher with oxygen, reflecting higher temperatures and altered luminous species. Swirl improved mixing, reducing CO and CxHy emissions with air, but oxygen combustion increased NOx due to elevated temperatures and potential nitrogen ingress. Higher swirl angles mitigated NOx in oxygen cases. These findings underscore the critical role of swirl and oxidizer type in optimizing flame stability, efficiency, and emissions in combustion systems.
Keywords
Swirl effect
Propane
Oxygen
Air
Non-premixed flame
Light intensity
Subjects

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Journal of Applied and Computational Mechanics
Volume 12, Issue 2
Spring 2026
Pages 671-681