NO and OH* emission characteristics of very-lean to stoichiometric ammonia–hydrogen–air swirl flames
Name:
Zhu et al,ProCI, 2020_NO and OH emission.pdf
Size:
5.715Mb
Format:
PDF
Description:
Accepted manuscript
Embargo End Date:
2022-09-09
Type
ArticleKAUST Department
Clean Combustion Research CenterMechanical Engineering Program
Physical Science and Engineering (PSE) Division
high-pressure combustion (HPC) Research Group
Date
2020-09-09Online Publication Date
2020-09-09Print Publication Date
2020-09Embargo End Date
2022-09-09Submitted Date
2019-11-06Permanent link to this record
http://hdl.handle.net/10754/665068
Metadata
Show full item recordAbstract
One of the main concerns regarding ammonia combustion is its tendency to yield high nitric oxide (NO) emissions. Burning ammonia under slightly rich conditions reduces the NO mole fraction to a low level, but the penalties are poor combustion efficiency and unburnt ammonia. As an alternative solution, this paper reports the experimental investigation of premixed swirl flames fueled with ammonia-hydrogen mixtures under very-lean to stoichiometric conditions. A gas analyzer was used to measure the NO mole fraction in the flame and post flame regions, and it was found that low NO emissions (as low as 100 ppm) in the exhaust were achieved under very lean conditions (ϕ ≈ 0.40). Low NO emission was also possible at higher equivalence ratios, e.g. ϕ = 0.65, for very large ammonia fuel fractions (XNH3 > 0.90). 1-D flame simulations were performed to elaborate on experimental findings and clarify the observations of the chemical kinetics. In addition, images of OH* chemiluminescence intensity were captured to identify the flame structure. It was found that, for some conditions, the OH* chemiluminescence intensity can be used as a proxy for the NO mole fraction. A monotonic relationship was discovered between OH* chemiluminescence intensities and NO mole fraction for a wide range of ammonia-hydrogen blends (0.40 < ϕ < 0.90 and 0.25 < XNH3 < 0.90), making it possible to use the low-cost OH* chemiluminescence technique to qualify NO emission of flames fueled with hydrogen-enriched ammonia blends.Citation
Zhu, X., Khateeb, A. A., Guiberti, T. F., & Roberts, W. L. (2020). NO and OH* emission characteristics of very-lean to stoichiometric ammonia–hydrogen–air swirl flames. Proceedings of the Combustion Institute. doi:10.1016/j.proci.2020.06.275Sponsors
Research reported in this paper was supported by King Abdullah University of Science and Technology (KAUST). Our thanks to Dr. Y. Li for his assistance with 1-D laminar flame computations.Publisher
Elsevier BVAdditional Links
https://linkinghub.elsevier.com/retrieve/pii/S1540748920303679ae974a485f413a2113503eed53cd6c53
10.1016/j.proci.2020.06.275