Suppression of NOx emissions by intensive strain in lean premixed hydrogen flamelets

Journal Article (2023)
Author(s)

A. Porcarelli (TU Delft - Flight Performance and Propulsion)

B. Kruljevic (TU Delft - Flight Performance and Propulsion)

Ivan Langella (TU Delft - Flight Performance and Propulsion)

Research Group
Flight Performance and Propulsion
Copyright
© 2023 A. Porcarelli, B. Kruljević, I. Langella
DOI related publication
https://doi.org/10.1016/j.ijhydene.2023.08.110
More Info
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Publication Year
2023
Language
English
Copyright
© 2023 A. Porcarelli, B. Kruljević, I. Langella
Research Group
Flight Performance and Propulsion
Volume number
49
Pages (from-to)
413-431
Reuse Rights

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Abstract

NOx formation in premixed, highly-strained, pure hydrogen-air flamelets is investigated at lean conditions. Detailed-chemistry, one-dimensional and two-dimensional simulations are performed on a reactants-to-products configuration with varying applied strain rate. The results highlight for the first time for lean pure-hydrogen flamelets that NOx emissions are suppressed as strain rate is increased. The most substantial decrease is observed across the thermal NOx formation pathway. Here the suppression of NOx is triggered by a redistribution across the flamelet of the radicals involved in the pathway reactions. A comparison with methane flamelets is further performed to understand to what extent the observed trends with strain can be specifically linked to hydrogen burning features. Similar NOx suppression trends with strain are also observed for increased pressure and different equivalence ratios, although with different rates of decrease. A correlation is proposed based on the observed results and further theoretical considerations, to predict NOx emissions according to applied strain rate and equivalence ratio.