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Lookup NU author(s): Vishnu MohanORCiD, Freddie Young, Dr Umair AhmedORCiD, Professor Nilanjan ChakrabortyORCiD
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
© 2024 The Author(s)Three-dimensional Direct Numerical Simulations (DNS) of turbulent premixed lean H2-air flames are performed for different equivalence ratios and initial turbulence intensities to investigate the influence of differential diffusion on the invariants of the velocity gradient tensor and local flow topologies. It is found that the effects of differential diffusion strengthen with a decrease in equivalence ratio. This difference results in more frequent super-adiabatic temperatures and higher positive dilatation rates for smaller values of equivalence ratio, having a significant impact on the flow topology distributions and their contributions to the scalar-turbulence interaction and vortex-stretching terms. The topologies associated with positive dilatation rates tend to occur at the curvatures associated with super-adiabatic temperatures for highly lean H2-air premixed flames. However, this tendency weakens with increasing equivalence ratio. These findings suggest that the chemical timescale must be accounted for in the modelling of viscous and scalar dissipation rates in lean hydrogen-air premixed flames.
Author(s): Mohan V, Young FW, Ahmed U, Chakraborty N
Publication type: Article
Publication status: Published
Journal: International Journal of Hydrogen Energy
Year: 2025
Volume: 98
Pages: 35-51
Print publication date: 13/01/2025
Online publication date: 06/12/2024
Acceptance date: 29/11/2024
Date deposited: 29/11/2024
ISSN (print): 0360-3199
ISSN (electronic): 1879-3487
Publisher: Elsevier Ltd
URL: https://doi.org/10.1016/j.ijhydene.2024.11.477
DOI: 10.1016/j.ijhydene.2024.11.477
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