Influence of variable swirl on emissions in a non-premixed fuel-flexible burner at elevated ambient conditions

Pugh, Daniel ORCID: https://orcid.org/0000-0002-6721-2265, Bowen, Philip ORCID: https://orcid.org/0000-0002-3644-6878, Navaratne, Rukshan, Goktepe, Burak, Giles, Anthony ORCID: https://orcid.org/0000-0002-1221-5987, Valera Medina, Agustin ORCID: https://orcid.org/0000-0003-1580-7133, Morris, Steven ORCID: https://orcid.org/0000-0001-5865-8911 and Vivoli, Robin 2024. Influence of variable swirl on emissions in a non-premixed fuel-flexible burner at elevated ambient conditions. Journal of Engineering for Gas Turbines and Power 146 (6) , 061006. 10.1115/1.4063786

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Abstract

As alternative fuels are designated for future energy applications, flexible combustor designs require considerable development to ensure stable operation with reduced NOx emissions. A non-premixed variable swirl burner was used to experimentally appraise changes in NO production pathways, with CH4 NH3, and H2 flames, alongside intermediate fuel blends. Maintaining an equivalent thermal power and flame temperature between fuels, preheated reactants (500 K) were supplied to the burner, with parametric changes made to pressure (1 - 6 bara) and swirl number (0.8 - 2.0). NO production was characterized, alongside variations in flame structure and topology, with a correlation demonstrated for exhaust emissions. NO production was shown to be sensitive to combustor pressure, providing an expected increase for CH4 and H2 flames. Emission profiles from both NH3 and H2 flames are shown to be significantly augmented by a change in swirl number. As NH3 fractions were increased in the H2 blend, a decaying trend in NO emissions was observed with an increase in pressure, and as a function of mixture ratio. However, this behaviour was markedly augmented by a change in swirl number and suggests that further reductions may be possible at increased pressure. At the low swirl/high pressure condition the NH3/H2 blend outperformed pure H2, providing lower NO concentrations. Emissions data were normalised using the traditional dry/O2 correction, alongside mass scaled by thermal power, with a comparison provided. The corresponding differences in emission formation pathways were investigated, alongside high-speed OH* chemiluminescence to further elucidate findings.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Engineering
Publisher:	American Society of Mechanical Engineers
ISSN:	0742-4795
Date of First Compliant Deposit:	23 October 2024
Date of Acceptance:	8 October 2023
Last Modified:	26 Nov 2024 12:15
URI:	https://orca.cardiff.ac.uk/id/eprint/164707

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