Large-eddy simulation of hydrogen ignition and NO x [jls-end-space/] formation in diesel-pilot dual-fuel combustion
Treacy, Mark LU ; Moratto, Federico LU ; Hadadpour, Ahmad LU ; Rorimpandey, Patrick ; Chan, Qing N. ; Kook, Sanghoon ; Bai, Xue Song LU and Fatehi, Hesameddin LU
(2026)
In International Journal of Spray and Combustion Dynamics
18(1).
p.54-69
- Abstract
This study examines the dynamics of diesel/hydrogen dual-fuel combustion in a constant-volume vessel under compression ignition engine conditions, where a small pilot n-heptane (a surrogate of diesel) injection precedes a long-duration hydrogen main injection containing 93.6% of the energy share. We investigate how pilot n-heptane flame and hydrogen injection affect emissions and combustion by systematically varying the dwell time ( Δ[jls-end-space/]t between the end of n-heptane injection and the start of hydrogen injection) while keeping the injection rate profile fixed. Large eddy simulations with detailed chemistry are performed at vessel conditions of 890 K, 52 bar, and 21 vol.% O 2[jls-end-space/], and compared against Schlieren... (More)
This study examines the dynamics of diesel/hydrogen dual-fuel combustion in a constant-volume vessel under compression ignition engine conditions, where a small pilot n-heptane (a surrogate of diesel) injection precedes a long-duration hydrogen main injection containing 93.6% of the energy share. We investigate how pilot n-heptane flame and hydrogen injection affect emissions and combustion by systematically varying the dwell time ( Δ[jls-end-space/]t between the end of n-heptane injection and the start of hydrogen injection) while keeping the injection rate profile fixed. Large eddy simulations with detailed chemistry are performed at vessel conditions of 890 K, 52 bar, and 21 vol.% O 2[jls-end-space/], and compared against Schlieren and apparent heat-release rate derived from measurements. The simulations show a good agreement with experimental results regarding ignition onset and flame propagation. The pilot n-heptane ignites rapidly at the spray tip, ∼[jls-end-space/]0.5 ms after injection; thereafter, the flame propagates upstream toward the injector nozzle. The hydrogen jet ignites nearly immediately upon its intersection with the n-heptane flame. Varying the dwell time between the end of n-heptane injection and the start of hydrogen injection significantly affects hydrogen ignition timing, peak heat release rates, and NO x emissions. Notably, while longer dwell times lead to delayed hydrogen ignition and lower NO x formation, medium dwell times result in higher NO x emissions, showing a complex non-linear relationship between hydrogen-diesel combustion and NO x emissions.
(Less)
- author
- Treacy, Mark
LU
; Moratto, Federico
LU
; Hadadpour, Ahmad
LU
; Rorimpandey, Patrick
; Chan, Qing N.
; Kook, Sanghoon
; Bai, Xue Song
LU
and Fatehi, Hesameddin
LU
- organization
- publishing date
- 2026-03
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- compression ignition, direct injection, Hydrogen, internal combustion engine, NO
- in
- International Journal of Spray and Combustion Dynamics
- volume
- 18
- issue
- 1
- pages
- 16 pages
- publisher
- SAGE Publications
- external identifiers
-
- scopus:105033748348
- ISSN
- 1756-8277
- DOI
- 10.1177/17568277261420744
- language
- English
- LU publication?
- yes
- additional info
- Publisher Copyright: © The Author(s) 2026. This article is distributed under the terms of the Creative Commons Attribution 4.0 License (https://creativecommons.org/licenses/by/4.0/) which permits any use, reproduction and distribution of the work without further permission provided the original work is attributed as specified on the SAGE and Open Access page (https://us.sagepub.com/en-us/nam/open-access-at-sage).
- id
- 9bb49186-fa22-4134-9d75-daf84676ed68
- date added to LUP
- 2026-05-27 15:50:39
- date last changed
- 2026-05-27 15:51:12
@article{9bb49186-fa22-4134-9d75-daf84676ed68,
abstract = {{<p>This study examines the dynamics of diesel/hydrogen dual-fuel combustion in a constant-volume vessel under compression ignition engine conditions, where a small pilot n-heptane (a surrogate of diesel) injection precedes a long-duration hydrogen main injection containing 93.6% of the energy share. We investigate how pilot n-heptane flame and hydrogen injection affect emissions and combustion by systematically varying the dwell time ( Δ[jls-end-space/]t between the end of n-heptane injection and the start of hydrogen injection) while keeping the injection rate profile fixed. Large eddy simulations with detailed chemistry are performed at vessel conditions of 890 K, 52 bar, and 21 vol.% O 2[jls-end-space/], and compared against Schlieren and apparent heat-release rate derived from measurements. The simulations show a good agreement with experimental results regarding ignition onset and flame propagation. The pilot n-heptane ignites rapidly at the spray tip, ∼[jls-end-space/]0.5 ms after injection; thereafter, the flame propagates upstream toward the injector nozzle. The hydrogen jet ignites nearly immediately upon its intersection with the n-heptane flame. Varying the dwell time between the end of n-heptane injection and the start of hydrogen injection significantly affects hydrogen ignition timing, peak heat release rates, and NO x emissions. Notably, while longer dwell times lead to delayed hydrogen ignition and lower NO x formation, medium dwell times result in higher NO x emissions, showing a complex non-linear relationship between hydrogen-diesel combustion and NO x emissions.</p>}},
author = {{Treacy, Mark and Moratto, Federico and Hadadpour, Ahmad and Rorimpandey, Patrick and Chan, Qing N. and Kook, Sanghoon and Bai, Xue Song and Fatehi, Hesameddin}},
issn = {{1756-8277}},
keywords = {{compression ignition; direct injection; Hydrogen; internal combustion engine; NO}},
language = {{eng}},
number = {{1}},
pages = {{54--69}},
publisher = {{SAGE Publications}},
series = {{International Journal of Spray and Combustion Dynamics}},
title = {{Large-eddy simulation of hydrogen ignition and NO x [jls-end-space/] formation in diesel-pilot dual-fuel combustion}},
url = {{http://dx.doi.org/10.1177/17568277261420744}},
doi = {{10.1177/17568277261420744}},
volume = {{18}},
year = {{2026}},
}