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Lookup NU author(s): Dr Hamid Kavari, Professor Nilanjan ChakrabortyORCiD
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
© 2026 The Authors. Published by Elsevier Ltd on behalf of Hydrogen Energy Publications LLC. This is an open access article under the CC BY license. http://creativecommons.org/licenses/by/4.0/An a priori assessment of first-order Conditional Moment Closure (CMC) for turbulent lean H2–air premixed flames was conducted using Direct Numerical Simulation (DNS) data for statistically planar flames with equivalence ratios of 0.4 and 0.7 under varying turbulence intensities. A presumed β-Probability Density Function (PDF) has been shown to capture the qualitative behaviour of the Favre-conditioned PDF of the reaction progress variable, although quantitative discrepancies remain. Existing models for conditional mean velocity perform satisfactorily, while conditional scalar dissipation rate models reproduce DNS trends qualitatively but with quantitative discrepancies linked to inaccuracies in Favre-averaged scalar dissipation rate and PDF predictions. First-order CMC predicts conditional mean reaction rates accurately for H2 and H2O but overpredicts O2 reaction rates due to elevated conditional variance. DNS data also reveal counter-gradient conditional scalar fluxes associated with sub-unity Lewis number effects, highlighting the need for improved scalar flux closures.
Author(s): Kavari H, Chakraborty N
Publication type: Article
Publication status: Published
Journal: International Journal of Hydrogen Energy
Year: 2026
Volume: 253
Print publication date: 22/07/2026
Online publication date: 28/06/2026
Acceptance date: 23/06/2026
Date deposited: 14/07/2026
ISSN (print): 0360-3199
ISSN (electronic): 1879-3487
Publisher: Elsevier
URL: https://doi.org/10.1016/j.ijhydene.2026.156214
DOI: 10.1016/j.ijhydene.2026.156214
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