Modelling of turbulent premixed swirl flames for 70/30 vol% NH3/H2 fuel-air mixtures

Jójka, Joanna, Alnasif, Ali, Mashruk, Syed and Valera-Medina, Agustin ORCID: https://orcid.org/0000-0003-1580-7133 2024. Modelling of turbulent premixed swirl flames for 70/30 vol% NH3/H2 fuel-air mixtures. Presented at: The 19th edition of the International Conference on Numerical Combustion, Kyoto, Japan, 7-10 May 2024.

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Abstract

Accurate prediction of ammonia turbulent combustion emissions is crucial for the further development of combustionsystems. Fuel-air mixtures with a 70/30 vol% NH3/H2 ratio were numerically investigated for a premixed burnersetup with a fixed power of 10kW. RANS calculations were performed with Reynolds stress transport using a complex chemistry and species transportmodel with respect to thermal and mixture averaged diffusion. Turbulence-chemistry interaction was modelled usingthe Eddy Dissipation Concept with Stagni and Nakamura kinetic reaction mechanisms. The numerical results were evaluated in terms of flame shape, flame stability and emissions, with a focus on the NO,N2O and NO2 shares in the flue gases and the unburned NH3 prediction capabilities of the model. Qualitative and quantitative agreement was achieved within the equivalence ratio (ϕ) range of 0.8-1.2, while therelative error of the NO predictions did not exceed 3.5% with respect to the uncertainty of the experimental results.Gradients of NH3 and NO shares in the flue gases for the modelled turbulent flames were found to be shiftedtowards stoichiometric conditions compared to the same mixture and mechanism for a burner-stabilised stagnation1D flame outcome. A significant overprediction of NO emission was expected for very lean mixtures ϕ = 0.6, asdeviations can be related to the simplification of fine structure reaction fractions commonly used in the EDC model.Despite its limitations in the very lean conditions, the model correctly predicted a decrease in NO concentration inthe flue gases, associated with a rapid increase in N2O emission.

Item Type:	Conference or Workshop Item (Paper)
Status:	In Press
Schools:	Engineering
Funders:	Department for Energy Security & Net Zero (DESNZ)
Date of First Compliant Deposit:	9 June 2024
Date of Acceptance:	19 January 2024
Last Modified:	11 Jul 2024 01:26
URI:	https://orca.cardiff.ac.uk/id/eprint/169625

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