Effects of Oxygen Enrichment and Air Humidification on the Combustion and Emissions of the Biodiesel Marine Diesel Engine
With increasingly strict emission regulations, research on diesel engine combustion and emissions is urgently needed. This study conducted computational fluid dynamics modeling on diesel engines. The effects of intake humidity and oxygen concentration of a diesel engine on the combustion emission of...
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| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-01-01
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| Series: | Journal of Marine Science and Engineering |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2077-1312/13/2/271 |
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| Summary: | With increasingly strict emission regulations, research on diesel engine combustion and emissions is urgently needed. This study conducted computational fluid dynamics modeling on diesel engines. The effects of intake humidity and oxygen concentration of a diesel engine on the combustion emission of biodiesel were studied. The results indicate that when the humidity ratio is below 0.4 (WR = 0.4), intake humidification has a certain promoting effect on the combustion reaction process. Water molecule pyrolysis can promote the pyrolysis of biodiesel, and the peak pressure in the cylinder slightly increases. As the intake humidification ratio increases, the cylinder temperature decreases, and the oxygen concentration also decreases due to the increase in water molecular weight. The combustion reaction process is suppressed, and the cylinder pressure decreases. When the humidity ratio is 1 (WR = 1), the peak pressure decreases by 2.61% compared to when it is not humidified (WR = 0). The concentration of O radicals decreases with an increase in humidity ratio. When WR = 1.0, the emissions of NO<sub>x</sub> decreased by 55.02%, but with the decrease in oxygen concentration in the high-temperature area, the emissions of soot increased. The results indicate that as the oxygen concentration increases, the cylinder pressure and average temperature increase, the ignition-delay time decreases, the heat-release rate increases, and it ultimately leads to an increase in NO<sub>x</sub> emissions. |
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| ISSN: | 2077-1312 |