Numerical Investigation of Methanol Ignition Sequence in an Optical PPC Engine with Multiple Injection Strategies

Pucilowski, Mateusz; Fatehi, Hesameddin; Jangi, Mehdi; Lönn, Sara Larsson; Matamis, Alexios; Andersson, Öivind; Richter, Mattias; Bai, Xue‐Song

doi:10.4271/2019-24-0007

Cited by 5 publications

(2 citation statements)

References 34 publications

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“…To analyze the combustion kinetics during the combustion process, four important combustion periods were selected, including CA1, CA5, CA10, and CA50 timing, corresponding to the ignition timing, initial combustion period, premixed-combustion period, and mixing-controlled combustion period, respectively. The ignition timing and initial combustion phase is essential to the combustion process. − The premixed-combustion and mixing-controlled-combustion periods are the main combustion process, which is essential to the control of engine power output.…”

Section: Results and Discussionmentioning

confidence: 99%

Investigation of the Combustion Kinetics Process in a High-Pressure Direct Injection Natural Gas Marine Engine

Liu

et al. 2021

Energy Fuels

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The detailed combustion kinetic processes of a high-pressure direct injection (HPDI) natural gas (NG) marine engine was investigated in the present work. A postprocessing code was employed to visualize the characteristic reactions that determine the combustion process. To evaluate the effect of mixture stratification on the combustion process, various NG injection timings were employed and four representative combustion periods were selected, including the timings when 1% (CA1), 5% (CA5), 10% (CA10), and 50% (CA50) of the total fuel energy are released. A higher heat release rate (HRR) was generated with a more advanced NG start of injection (SOI) timing, which, however, had limited effects on the main representative exothermic reactions (REXRs) within the high heat release (HHR) region and the dominant formation reactions of CH 2 O and OH, which are known as the indicators of low heat release (LHR) and HHR, respectively. Besides, for different NG SOI timing simulation, the consumption of CH 4 was all dominated by reactions H + CH 4 = CH 3 + H 2 and OH + CH 4 = CH 3 + H 2 O and the dominated REXR of the LHR region was reaction CH 3 + O 2 = CH 3 O 2 . Furthermore, with an advanced NG injection timing, significant changes were observed for the reaction paths of CH 2 , CH 2 O, and HCO from the premixed-combustion phase (CA10) to the mixing-controlled combustion phase (CA50). The results of the present study are able to provide a theoretical fundamental for the practical control of the HPDI NG marine engine.

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Section: Results and Discussionmentioning

confidence: 99%

Investigation of the Combustion Kinetics Process in a High-Pressure Direct Injection Natural Gas Marine Engine

Liu

et al. 2021

Energy Fuels

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“…It has been widely employed in previous studies on spray combustion including dual-fuel combustion. 20,21 The Kelvin–Helmholtz and Rayleigh–Taylor models were employed to model the diesel droplet atomization and breakup. 22 The calculation of heat exchange and evaporation of droplets were accomplished using the Ranz–Marshall 23 and Spalding models 24 respectively; however, the process of droplet boiling was not considered in this simulation.…”

Section: Computational Modelmentioning

confidence: 99%

Experimental and numerical analysis of unburned ammonia and nitrous oxide emission characteristics in ammonia/diesel dual-fuel engine

Niki

2023

International Journal of Engine Research

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Ammonia (NH3) combustion has been investigated as a carbon-free fuel for internal combustion engines. The marine sector attempts to use NH3 as fuel for diesel engines. However, NH3 combustion in diesel engines can emit unburned NH3 and nitrous oxide (N2O) via the greenhouse effect, and the mechanisms of emission production remain unclear. In this study, the combustion of a premixed NH3–diesel dual-fuel initiated by a pilot fuel is investigated experimentally and numerically. The experiments reveal a change in combustion phasing and emission characteristics for up to 80% of the energy fraction of NH3. As the energy fraction of NH3 increases, the onset of combustion is delayed, the center of combustion is slightly advanced and then retracted, and the end of combustion is slightly advanced. NO and unburned NH3 emissions increased, whereas CO emission decreased as the energy fraction of NH3 increased; by contrast, N2O emissions increased. However, the increase in N2O diminished when the energy fraction of NH3 increased by 40% or more. Computation fluid dynamics simulations based on n-heptane and ammonia reaction kinetics qualitatively reproduced the experimental results. The numerical analysis facilitates the understanding of the underlying phenomena of emission via ammonia–diesel dual-fuel combustion. N2O formation can be categorized into two stages: a steep formation of N2O with main heat release and CO2 production, followed by a relatively low formation rate of N2O with a decreasing rate of NH3 decomposition and reduction in CO2 production. The early injection of pilot fuel allowed the pilot fuel to distribute to the wide area of the combustion chamber and NH3 to rapidly combust without remaining N2O. The rapid combustion eliminates the second stage of relatively slow combustion, which generated N2O. The low NH3 and N2O emissions observed experimentally with the early pilot fuel injection may be due to this mechanism

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Fuel Injection Strategies for Alcohol Utilization in Combustion Engines

Sahu

Shukla

2022

Energy, Environment, and Sustainability

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Numerical Investigation of Methanol Ignition Sequence in an Optical PPC Engine with Multiple Injection Strategies

Cited by 5 publications

References 34 publications

Investigation of the Combustion Kinetics Process in a High-Pressure Direct Injection Natural Gas Marine Engine

Investigation of the Combustion Kinetics Process in a High-Pressure Direct Injection Natural Gas Marine Engine

Experimental and numerical analysis of unburned ammonia and nitrous oxide emission characteristics in ammonia/diesel dual-fuel engine

Fuel Injection Strategies for Alcohol Utilization in Combustion Engines

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