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Jet ignition characteristics of ammonia-hydrogen passive pre-chamber: Emphasis on equivalence ratio and hydrogen/ammonia ratio.
- Source :
-
Energy Conversion & Management . Sep2024, Vol. 315, pN.PAG-N.PAG. 1p. - Publication Year :
- 2024
-
Abstract
- • Role of hydrogen/ammonia ratio and equivalence ratio in jet ignition is identified. • The high hydrogen/ammonia ratio enhances ignition by improving mixture reactivity. • As hydrogen/ammonia ratio increases from 0 % to 20 %, ignition delay decreases by 70 %. • Equivalence ratio seriously affects ignition and flame expansion under lean-burning. Ammonia-hydrogen blend fuels offer the potential for zero-carbon emissions in internal combustion (IC) engines. To improve combustion performance, considerable attention has been focused on pre-chamber jet ignition technologies. Passive pre-chamber featuring a simple structure can be installed in the spark plug hole without modifying the cylinder head. However, the jet ignition characteristics of ammonia-hydrogen passive pre-chambers are not fully understood, and there is a lack of visualized evidence on how critical parameters (e.g., equivalence ratio and hydrogen/ammonia ratio) impact ignition processes. This work investigated the effects of equivalence ratio and hydrogen/ammonia ratio on ammonia-hydrogen jet ignition characteristics in a rapid compression machine with passive pre-chamber. High-speed photography and instantaneous pressure acquisition were employed to capture detailed ignition and combustion evolutions. Results show that under low hydrogen/ammonia ratio conditions, there exists a combustion regime with noticeable fluctuations in jet penetration, indicating degenerate ignition performance. As the hydrogen/ammonia ratio increases from 0 % to 20 %, the ignition delay time of mixtures in the main chamber is reduced by 70 %, suggesting an improved overall ignition performance. Regarding the equivalence ratio, more pronounced effects on jet ignition and flame propagation are identified under lean-burning conditions. For mixtures at the hydrogen/ammonia ratio of 20 %, as the equivalence ratio increases from 0.6 to 0.8 and from 0.8 to 1.0, the decay rates for 10 %–90 % combustion duration are 82.5 % and 20.6 %, respectively. Besides, with the increase of equivalence ratio, flame initiation is shifted from the jet head to the side surface. The role of hydrogen/ammonia ratio and equivalence ratio is different, with the former modifying mixture reactivity while the latter affecting ignition energy. [ABSTRACT FROM AUTHOR]
- Subjects :
- *SPARK plugs
*HIGH-speed photography
*COMBUSTION
*AMMONIA
*HYDROGEN
Subjects
Details
- Language :
- English
- ISSN :
- 01968904
- Volume :
- 315
- Database :
- Academic Search Index
- Journal :
- Energy Conversion & Management
- Publication Type :
- Academic Journal
- Accession number :
- 178857706
- Full Text :
- https://doi.org/10.1016/j.enconman.2024.118785