Differential diffusion effects in the near field of non-premixed NH3/H2/N2-air jet flames at elevated pressure

Hao Tang, Chaobo Yang, Yedhu Krishna, Guoqing Wang, William L. Roberts, Thibault Guiberti, Gaetano Magnotti

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


Differential diffusion (diff-diff) effects are analyzed in both non-premixed laminar and turbulent NH3-H2-N2 jet flames at 5 bar using 1D quantitative Raman scattering measurements. The two target flames feature fuel compositions simulating a 14% and a 28% NH3 cracking ratio. A diff-diff parameter is introduced for ammonia combustion, analogous to the definition used for hydrocarbon flames. Measurements in laminar flames, compared to Chemkin simulation featuring multi-component transport show that the instrument is capable of measuring the mean diff-diff parameter, but that single-shot measurements are compromised by the large sensitivity of the parameter to errors in N2 and NH3 mass fractions. The analysis of the diff-diff parameter in turbulent flames shows that both flames have strong differential diffusion in the near field up to an axial distance of 10 diameters (Z/D = 10), then the turbulent mixing becomes dominant further downstream. The flame with a 28% NH3 cracking ratio exhibits a higher diff-diff parameter especially in the low-temperature region (
Original languageEnglish (US)
Pages (from-to)111020
JournalExperimental Thermal and Fluid Science
StatePublished - Aug 6 2023

Bibliographical note

KAUST Repository Item: Exported on 2023-08-08
Acknowledgements: The research reported in this publication was funded by King Abdullah University of Science and Technology (KAUST).

ASJC Scopus subject areas

  • General Chemical Engineering
  • Mechanical Engineering
  • Nuclear Energy and Engineering
  • Fluid Flow and Transfer Processes
  • Aerospace Engineering


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