Growth and oxidation of graphitic crystallites in soot particles within a laminar diffusion flame

Hayashida, Kazuhiro; Nagaoka, Shogo; Ishitani, Hiromi

doi:10.1016/j.fuel.2014.03.008

Cited by 38 publications

(25 citation statements)

References 56 publications

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“…Piston impingement was also observed for the experiment with an engine rotational frequency of ω = 1500 [RPM] and a single injection of 26 [mg] of fuel and for the experiment at the lower engine rotational frequency of ω = 1000 [RPM] and a single injection of 18 [mg]. Pool fires on the piston crown at the location of the fuel spray impingement on the piston crown was observed in both cases.…”

Section: Imagingmentioning

confidence: 78%

“…Equal concentrations of the presumed aggregate precursor species were measured in both cases and the reduction in soot was attributed to the greater abundance of OH radicals from the O 2 and oxidation of the soot aggregates by OH. The formation, structure and oxidation of soot in a propane concentric coflow diffusion flame at atmospheric pressure was investigated in a study by [26]. The soot size measured by Raman scattering of sampled soot and the soot volume fraction determined with laser induced incandescence decreased as the intensity of the laser induced fluorescence of OH increased suggesting soot oxidation by OH.…”

Section: Soot Formation and Oxidationmentioning

confidence: 99%

“…The fuel spray was directly ignited by the spark as a result of the spark timing, as is also discussed in Section 4. The fuel spray from a single injection of 26 [mg] of fuel could not be ignited directly while the fuel spray was passing the spark plug. Ignition was achieved with a spark beginning after the fuel spray had passed the spark plug.…”

Section: Injection Strategymentioning

confidence: 99%

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In cylinder visualization of stratified combustion of E85 and main sources of soot formation

Johansen

Hemdal

2015

Fuel

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The combustion process and soot formation in spark ignited spray guided stratified combustion of E85 was investigated in a single cylinder optical engine with direct injection of fuel using an outward opening piezo actuated injector. The effect of engine rotation frequency, fuel quantity, injection sequence and ignition timing was studied. Combustion, soot formation and soot oxidation was analysed using cylinder pressure measurements, images recorded using high speed video cameras, the flame emission spectrum and OH * chemiluminescence and soot incandescence imaging. A maximum injection duration was found to exist for direct ignition of the fuel spray. Engine rotation frequency had little effect on the initial and maximum rate of combustion. The maximum rate of combustion decreased with increasing cycle fuel mass when a single injection was used. The rate of combustion and indicated mean effective pressure increased and the combustion variability decreased when the single injection was split into multiple injections in close succession to deliver the same total fuel mass and the last fuel spray was ignited. Ignition of the first fuel spray resulted in a more pronounced change. The absence of soot incandescence during the initial flame propagation suggested flame propagation in a partially mixed fuel and air mixture with stoichiometric to fuel lean regions. A single fuel injection resulted in piston pool fires due to fuel spray impingement on the piston and was the primary source of soot formation. The pool fires persisted until after conditions favourable to oxidation of the soot had ended. Soot formation in the gas phase occurred while favourable soot oxidation conditions existed and was efficiently oxidized. The magnitude of the piston pool fires was reduced using multiple injections. The reduction is attributed to a reduction of the fuel spray penetration length and a smaller effective injection orifice area, resulting in a shorter total duration of fuel spray impingement on the piston crown. Soot formation occurred primarily in the gas phase when the first of two fuel sprays was ignited and persisted due to the second fuel spray entering an existing flame leading to fuel rich combustion.

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Section: Imagingmentioning

confidence: 78%

Section: Soot Formation and Oxidationmentioning

confidence: 99%

Section: Injection Strategymentioning

confidence: 99%

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In cylinder visualization of stratified combustion of E85 and main sources of soot formation

Johansen

Hemdal

2015

Fuel

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“…Building on this extensive spectroscopic literature, we also analyzed our data by using a three‐peak model by using the designation D1 for the D band, centered around 1350 cm −1 , in the three‐peak analysis and adding a hypothetical additional peak, which we will designate D3 following the notation of Sadezky . We used a Gaussian lineshape for the D3 peak and Lorentz lineshapes for the D1 and G peaks following the practice of Sadezky and others . These lineshapes gives better stability and a lower residual sum than other combinations of Lorentzian and Gaussian peaks.…”

Section: Spectral Parameter Determinationmentioning

confidence: 87%

“…[30] We used a Gaussian lineshape for the D3 peak and Lorentz lineshapes for the D1 and G peaks following the practice of Sadezky [30] and others. [32,33,[38][39][40] These lineshapes gives better stability and a lower residual sum than other combinations of Lorentzian and Gaussian peaks. The three-peak model provides an eight-parameter description of the observed lineshapes: the widths and peak positions of the D1, G, and D3 spectral peaks and the relative peak intensities I D1 /I G and I D3 /I G .…”

Section: Spectral Parameter Determinationmentioning

confidence: 99%

Characterizing the age of ancient Egyptian manuscripts through micro‐Raman spectroscopy

Goler

Yardley

Cacciola

et al. 2016

J. Raman Spectrosc.

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We report the first in‐depth, systematic study of the Raman spectra of black pigments on ancient Egyptian papyri with well‐specified dates from the 4th century bce to the 10th century ce. The observed spectra are all characteristic of carbon black, but the shapes of the spectra change systematically with the manuscript date, a striking observation given the time span represented. We conclude that the pigments for these papyri were manufactured by using similar processes. We attribute these experimentally observed changes to chemical degradation, possibly the result of the oxidation of both amorphous carbon and crystalline aromatic carbon within these pigments. This investigation offers new insights into the ink materials used in ancient Egypt and provides a possible basis for a new nondestructive means for estimating the dates of ancient papyri. Copyright © 2016 John Wiley & Sons, Ltd.

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3D mapping of polycyclic aromatic hydrocarbons, hydroxyl radicals, and soot volume fraction in sooting flames using FRAME technique

et al. 2021

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We report the three-dimensional (3D) mapping of polycyclic aromatic hydrocarbons (PAHs), soot, and hydroxyl radicals (OH) in ethylene/air diffusion flames. A structured illumination-based frequency recognition algorithm for multiple exposures (FRAME) approach is combined with sample translation to intersect the flame in several two-dimensional planes. The FRAME technique has been used for recording a snapshot of multiple species on a single camera. It relies on extracting the amplitude of spatial modulation of two or more probed species encoded on a single sub-image. Here, the FRAME technique is first applied for simultaneous imaging of PAH by laser-induced fluorescence (PAH-LIF) and soot by laser-induced incandescence (LII). Sequentially, it is employed for simultaneous mapping of OH-LIF and soot-LII. The LII signal is converted to absolute soot volume fraction (fv) maps using a line-of-sight light extinction measurement. Finally, we have demonstrated the approach for layer-wise 2D imaging of soot volume fraction and averaged 3D mapping of multiple species.

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Growth and oxidation of graphitic crystallites in soot particles within a laminar diffusion flame

Cited by 38 publications

References 56 publications

In cylinder visualization of stratified combustion of E85 and main sources of soot formation

In cylinder visualization of stratified combustion of E85 and main sources of soot formation

Characterizing the age of ancient Egyptian manuscripts through micro‐Raman spectroscopy

3D mapping of polycyclic aromatic hydrocarbons, hydroxyl radicals, and soot volume fraction in sooting flames using FRAME technique

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