Simultaneous Visualization of Natural Luminosity and Chemiluminescence of Dual Fuel Combustion in an Optically Accessible Engine

Cheng, Qiang; Ahmad, Zeeshan; Kaario, Ossi; Larmi, Martti

doi:10.4271/2020-01-0309

Cited by 7 publications

(5 citation statements)

References 33 publications

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“…9 (bottom). CH 2 O*, CH*, C 2 *, and CO 2 * chemiluminescence have been reported as HRR indicators [29][30][31] , location of the reaction zone 32,33 , an indicator of the equivalence ratio (ER) of the reacting mixture 34,35 . As observed in the reconstructed chemiluminescence emissions, it can be summarized that (1) CH 2 O* as a low-temperature HRR indicator only shows a reliable value at the beginning of the combustion with relatively low intensity.…”

Section: Resultsmentioning

confidence: 99%

Hyperspectral image reconstruction from colored natural flame luminosity imaging in a tri-fuel optical engine

Cheng

Karimkashi

Ahmad

et al. 2023

Sci Rep

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The detection of chemiluminescence from various radicals and molecules in a hydrocarbon flame can provide valuable information on the rate of local heat release, combustion stability, and combustion completeness. In this study, chemiluminescence from the combustion process is detected using a high-speed color camera within the broadband spectrum of visible light. Whereon, a novel hyperspectral reconstruction approach based on the physically plausible spectral reconstruction (PPSR) is employed to reconstruct the spectral chemiluminescence signals from 400 to 700 nm with a resolution of 10 nm to provide 31 different spectral channels. The reconstructed key chemiluminescence signals (e.g., CH*, CH2O*, C2*, and CO2*) from the color images are further analyzed to characterize the chemical kinetics and combustion processes under engine conditions. The spectral chemiluminescence evolution with engine crank angle is identified to comprehend the effect of H2 fraction on flame characteristics and combustion kinetics. Additionally, in this study, a detailed kinetic mechanism is adopted to deepen the theoretical understanding and describe the spectral chemiluminescence from H2/CH4 and H2/CH4/n-dodecane flames at relevant conditions for various species including OH*, CH*, C2*, and CO2*. The results indicate that the PPSR is an adequately reliable approach to reconstructing spectral wavelengths based on chemiluminescence signals from the color images, which can potentially provide qualitative information about the evolution of various species during combustion. Here, the reconstructed chemiluminescence images show less than 1% errors compared to the raw images in red, green, and blue channels. Furthermore, the reconstructed chemiluminescence trends of CH*, CH2O*, C2*, and CO2* show a good agreement with the detailed kinetics 0D simulation.

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Section: Resultsmentioning

confidence: 99%

Hyperspectral image reconstruction from colored natural flame luminosity imaging in a tri-fuel optical engine

Cheng

Karimkashi

Ahmad

et al. 2023

Sci Rep

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“…Categorized by their experimental apparatus, they can be divided into Constant Volume Chamber (CVC), 24 Rapid Compression Expansion Machine (RCEM), [25][26][27][28][29][30] single-/multi-cylinder optical engines. 25,[31][32][33][34][35][36][37][38][39][40][41] Dronniou et al 31 observed ignition occurred first in the near-wall region in the piston bowl, burning inwards. They identified the equivalence ratio of the premixed fuel to shape the heat release profile significantly.…”

Section: Pilot-ignited Lean-premixed Natural Gas Enginesmentioning

confidence: 99%

“…Categorized by their experimental apparatus, they can be divided into Constant Volume Chamber (CVC), 24 Rapid Compression Expansion Machine (RCEM), 25–30 single- /multi-cylinder optical engines . 25,31–41…”

Section: Introductionmentioning

confidence: 99%

Optical study on a heavy-duty natural gas dual-fuel engine applying POMDME as pilot fuel

Mühlthaler,

Prager,

Jaensch

2024

International Journal of Engine Research

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In this study, a fully optically accessible single-cylinder research engine is the basis for the visualization and generation of extensive knowledge about the in-cylinder processes of mixture formation, ignition, and combustion of alternative fuels for the dual-fuel combustion process. POMDME substitutes the fossil pilot fuel as a drop-in, non-sooting alternative to widely eliminate the NOx-PM tradeoff. Furthermore, an optimized ignition behavior, increased degrees of freedom in combustion phasing, and the pilot’s energy content are expected. The flame luminosity transmitted via an optical piston was split in the optical path to record the natural flame luminosity simultaneously with an RGB high-speed camera. The second channel consisted of OH chemiluminescence recording, isolated by a bandpass filter via an intensified monochrome high-speed camera. To investigate the combustion process spectrally, spatially, and temporally resolved in more detail, selected operating points were re-recorded via a high-speed imaging spectrograph. POMDME is benchmarked against regular diesel oil, according to EN590. Synthetic natural gas is applied as the primary gaseous fuel. Experimental sweeps along the overall pilot’s energy content (2%, 5%, 10%), injection pressure (500–1600 bar), and start of energizing (5–55 CAD bFTDC) are carried out. The given conditions result in decreased liquid-penetration length between 25% and 30% for the oxygenate, larger for earlier SOE and higher dilution. The lift-off length is nearer the liquid penetration length, increasing for higher rail pressures. The light-based ignition delay for EN590 is enlarged by 0.8 CAD after adding methane, while the oxygenate is not visibly retarded. Without methane, the oxygenate preceded EN590 by 0.6 CAD. The temporal and spatial position and extent of premixed, diffusive, and OH*, change significantly. RCCI operation at practically relevant 18.4 bar IMEP is demonstrated, highlighting the influence of the start of energizing variation with 51% decreased burn duration in the first half of combustion.

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“…To provide a direct validation, simultaneous visualization of the NFL and chemiluminescence, including broadband natural flame image (from 400-700 nm), CH2O* (400 nm), and CH* (430 nm) is performed based on a high-speed color camera (Photron SA-Z) and a bandpass filtered high-speed monochrome camera (Image Doubler + Bandpass filters + Phamton V2012) are captured for validation. More details of the experiments and results can be seen in our previous study [28].…”

Section: Fig 6 Comparison Of the Reconstructed Rgb Image And Raw Imagementioning

confidence: 99%

Hyperspectral Image Reconstruction from Colored Natural Flame Luminosity Imaging in a Tri-Fuel Optical Engine

Cheng

Karimkashi

Ahmad

et al. 2022

Preprint

Self Cite

View full text Add to dashboard Cite

The detection of chemiluminescence from various radicals and molecules in a hydrocarbon flame can provide valuable information on the rate of local heat release, combustion stability, and combustion completeness. In this study, chemiluminescence from the combustion process is detected using a high-speed color camera within the broadband spectrum of visible light. Whereon, a novel hyperspectral reconstruction approach based on the physically plausible spectral reconstruction (PPSR) is employed to reconstruct the spectral chemiluminescence signals from 400 to 700 nm with a resolution of 10nm to provide 31 different spectral channels. The reconstructed key chemiluminescence signals (e.g., CH*, CH2O*, C2*, and CO2*) from the color images are further analyzed to characterize the chemical kinetics and combustion processes under engine conditions. The spectral chemiluminescence evolution with engine crank angle is identified to comprehend the effect of H2 fraction on flame characteristics and combustion kinetics. Additionally, in this study, a detailed kinetic mechanism is adopted to deepen the theoretical understanding and describe the spectral chemiluminescence from H2/CH4 and H2/CH4/n-dodecane flames at relevant conditions for various species including OH*, CH*, C2*, and CO2*. The results indicate that the PPSR is an adequately reliable approach to reconstructing spectral wavelengths based on chemiluminescence signals from the color images, which can potentially provide qualitative information about the evolution of various species during combustion. Here, the reconstructed chemiluminescence images show less than 1% errors compared to the raw images in red, green, and blue channels. Furthermore, the reconstructed chemiluminescence trends of CH*, CH2O*, C2*, and CO2* show a good agreement with the detailed kinetics 0D simulation.

show abstract

Simultaneous Visualization of Natural Luminosity and Chemiluminescence of Dual Fuel Combustion in an Optically Accessible Engine

Cited by 7 publications

References 33 publications

Hyperspectral image reconstruction from colored natural flame luminosity imaging in a tri-fuel optical engine

Hyperspectral image reconstruction from colored natural flame luminosity imaging in a tri-fuel optical engine

Optical study on a heavy-duty natural gas dual-fuel engine applying POMDME as pilot fuel

Hyperspectral Image Reconstruction from Colored Natural Flame Luminosity Imaging in a Tri-Fuel Optical Engine

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