Influence of swirl intensity on combustion dynamics and emissions in an ammonia-enriched methane/air combustor
(2024) In Physics of Fluids 36(3).- Abstract
Ammonia (NH3) has been widely considered as a promising carbon-free energy and hydrogen carrier for various applications. The large-scale direct utilization of NH3 as fuel in gas turbine engines is currently attracting significant interest, with strong focuses on improving the efficiency and stability of the system and reducing the emissions of pollutants. The present study experimentally examined the impacts of swirl intensity on combustion stability and emissions in an NH3-enriched premixed swirl-stabilized CH4/air combustor under a wide range of equivalence ratios. Simultaneous high-speed OH* chemiluminescence and particle image velocimetry measurements suggested that increasing swirl... (More)
Ammonia (NH3) has been widely considered as a promising carbon-free energy and hydrogen carrier for various applications. The large-scale direct utilization of NH3 as fuel in gas turbine engines is currently attracting significant interest, with strong focuses on improving the efficiency and stability of the system and reducing the emissions of pollutants. The present study experimentally examined the impacts of swirl intensity on combustion stability and emissions in an NH3-enriched premixed swirl-stabilized CH4/air combustor under a wide range of equivalence ratios. Simultaneous high-speed OH* chemiluminescence and particle image velocimetry measurements suggested that increasing swirl intensity resulted in more compact flame shapes and expanded the recirculation zone, which promoted flame stability at higher NH3 ratios. However, under specified conditions, enhancing swirl intensity could increase the instability frequency and amplitude of pressure oscillations. The flame dynamics exhibited different behaviors depending on the swirl intensity. At high swirl intensity, the flames underwent high-frequency, small-amplitude periodic motion. At low swirl intensity, the flames oscillated axially with large amplitude and low frequency. For flow dynamics, the stability of the vortex at high swirl intensity contrasted with the periodic vortex shedding at low swirl intensity. Furthermore, the two-dimensional Rayleigh index indicated that the dominant positive thermoacoustic coupling regions were located near the flame shear layers and flame tail at low and high swirl intensities, respectively. Finally, the experimental results showed that swirl intensity affected pollutant emissions by influencing the temperature of combustion chamber and gas mixing efficiency. The pathway of fuel-type NOx was found to be dominant in the NOx emission of the NH3/CH4/air flames.
(Less)
- author
- Liu, Chunyu ; Yang, Haojie ; Ruan, Can LU ; Yu, Liang and Lu, Xingcai
- organization
- publishing date
- 2024-03-01
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Physics of Fluids
- volume
- 36
- issue
- 3
- article number
- 034123
- pages
- 22 pages
- publisher
- American Institute of Physics (AIP)
- external identifiers
-
- scopus:85188670725
- ISSN
- 1070-6631
- DOI
- 10.1063/5.0196764
- language
- English
- LU publication?
- yes
- additional info
- Publisher Copyright: © 2024 Author(s).
- id
- 6c697531-0c53-4dc8-8cd7-83eb277049d8
- date added to LUP
- 2024-04-06 10:08:08
- date last changed
- 2024-04-08 08:48:12
@article{6c697531-0c53-4dc8-8cd7-83eb277049d8,
abstract = {{<p>Ammonia (NH<sub>3</sub>) has been widely considered as a promising carbon-free energy and hydrogen carrier for various applications. The large-scale direct utilization of NH<sub>3</sub> as fuel in gas turbine engines is currently attracting significant interest, with strong focuses on improving the efficiency and stability of the system and reducing the emissions of pollutants. The present study experimentally examined the impacts of swirl intensity on combustion stability and emissions in an NH<sub>3</sub>-enriched premixed swirl-stabilized CH<sub>4</sub>/air combustor under a wide range of equivalence ratios. Simultaneous high-speed OH* chemiluminescence and particle image velocimetry measurements suggested that increasing swirl intensity resulted in more compact flame shapes and expanded the recirculation zone, which promoted flame stability at higher NH<sub>3</sub> ratios. However, under specified conditions, enhancing swirl intensity could increase the instability frequency and amplitude of pressure oscillations. The flame dynamics exhibited different behaviors depending on the swirl intensity. At high swirl intensity, the flames underwent high-frequency, small-amplitude periodic motion. At low swirl intensity, the flames oscillated axially with large amplitude and low frequency. For flow dynamics, the stability of the vortex at high swirl intensity contrasted with the periodic vortex shedding at low swirl intensity. Furthermore, the two-dimensional Rayleigh index indicated that the dominant positive thermoacoustic coupling regions were located near the flame shear layers and flame tail at low and high swirl intensities, respectively. Finally, the experimental results showed that swirl intensity affected pollutant emissions by influencing the temperature of combustion chamber and gas mixing efficiency. The pathway of fuel-type NOx was found to be dominant in the NOx emission of the NH<sub>3</sub>/CH<sub>4</sub>/air flames.</p>}},
author = {{Liu, Chunyu and Yang, Haojie and Ruan, Can and Yu, Liang and Lu, Xingcai}},
issn = {{1070-6631}},
language = {{eng}},
month = {{03}},
number = {{3}},
publisher = {{American Institute of Physics (AIP)}},
series = {{Physics of Fluids}},
title = {{Influence of swirl intensity on combustion dynamics and emissions in an ammonia-enriched methane/air combustor}},
url = {{http://dx.doi.org/10.1063/5.0196764}},
doi = {{10.1063/5.0196764}},
volume = {{36}},
year = {{2024}},
}