Reductions of PAH and Soot by Center Air Injection

Yamamoto, Kazuhiro; Takemoto, Masahiro

doi:10.3390/environments1010042

Cited by 5 publications

(5 citation statements)

References 20 publications

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“…The species CH 2 O and OH can be utilized for visualization of flame fronts and the heat release zone [ 7 , 8 ]. Species such as PAHs and soot particles are harmful pollutants generated from the combustion of fuels [ 9 , 10 , 11 , 12 , 13 , 14 , 15 ]. Due to the stricter emission norms, much attention has been given to the further understanding of the combustion chemistry, and especially the soot formation.…”

Section: Introductionmentioning

confidence: 99%

Application of FRAME for Simultaneous LIF and LII Imaging in Sooting Flames Using a Single Camera

Mishra

Boggavarapu

Chorey

et al. 2020

Sensors

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In this article, the application of the FRAME (Frequency Recognition Algorithm for Multiple Exposures) technique is presented for multi-species measurements in symmetric and asymmetric ethylene/air diffusion flames. Laminar Bunsen-type and swirled diffusion flames are investigated to gain a better understanding of sooting combustion. For this purpose, simultaneous imaging is conducted in terms of Laser-Induced Fluorescence (LIF) of Polycyclic Aromatic Hydrocarbons (PAH) and Laser-Induced Incandescence (LII) of soot particles. Subsequently, the approach is utilized for simultaneous imaging of hydroxyl (OH)-LIF and soot-LII. Here, the modulated LIF- and LII-signals are acquired together as a single sub-image—with a single exposure utilizing the full sensor size of a single camera. By employing the frequency-recognition algorithm on the single image, the LIF- and LII-signals are spectrally isolated—generating two individual LIF- and LII-images. The flame luminosity and out-of-focus light such as reflected surrounding laser light are detected as non-modulated signals in the unprocessed image. These unwanted signals are suppressed using the image post-processing, and, therefore, the image contrast of the two resulting images is improved. It is found that PAHs mainly exist in the inner region near the burner and are surrounded by soot. The majority of the OH is distributed on the outer edges of the flame—representing the reaction zone and soot-oxidation region of the flame.

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Section: Introductionmentioning

confidence: 99%

Application of FRAME for Simultaneous LIF and LII Imaging in Sooting Flames Using a Single Camera

Mishra

Boggavarapu

Chorey

et al. 2020

Sensors

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“…Hence In order to develop effective measures to reduce the toxicity of exhaust, it is essential to understand the complex processes which lead to PAH formation, and subsequent soot production. Open flame configurations can provide vital information in this regard, and both premixed and non-premixed flames have been used [4][5][6][7][8][9][10][11]. However, non-premixed flames have been observed to be more suitable to effectively track the early stages of PAH formation (such as acetylene production), and to understand the effect of fuel molecular structure on soot production [12].…”

Section: Introductionmentioning

confidence: 99%

“…The use of the non-intrusive planar laser induced fluorescence (PLIF) technique to detect PAHs in open flames is preferred over intrusive techniques (such as collecting samples using microprobes or microfilters), as it does not interfere with the flow field or disrupt concentration profiles [16], and can provide qualitative spatially and temporally resolved details of PAH formation in the flame. Several studies have successfully employed the laser induced fluorescence (LIF) technique in the study of PAH formation [6][7][8]17]. Liu et al [9] studied the effect of doping laminar gasoline flames (in a NDF configuration) with various alcohols (methanol, ethanol and n-butanol) on PAHs using PLIF.…”

Section: Introductionmentioning

confidence: 99%

Study of polycyclic aromatic hydrocarbons (PAHs) in hydrogen-enriched methane diffusion flames

Ezenwajiaku

Talibi

Doan

et al. 2019

International Journal of Hydrogen Energy

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Polycyclic aromatic hydrocarbons (PAHs) are the carcinogenic components of soot. Detailed understanding of PAH formation characteristics is required for development of effective strategies to curtail PAH formation and reduce soot in combustion devices. This study presents an experimental methodology to analyse PAH formation characteristics of a non-premixed methane-air flame with and without hydrogen (H2) addition, using simultaneous planar laser induced fluorescence (PLIF) imaging of PAH and hydroxyl radical (OH). OH PLIF was used to represent peak temperature regions in the flame front. One-dimensional, opposed-jet laminar non-premixed flame simulations were also carried out for the same fuel mixture conditions. This work describes comparison of trends from both sets of studies. PAH fluorescence intensity values were observed to increase with increasing height above burner, however this rate of increase reduced with H2 addition. This observed rate of change in PAH fluorescence (that is, PAH growth characteristics) is indicative of the sooting potential of the fuel mixture. PAH fluorescence from experiments and PAH concentration from simulation show strong reduction with increase in H2 addition. The percentage reduction in PAH fluorescence signal with H2 addition closer to the burner tip was of a similar magnitude to that observed with flame simulations. The reduction in PAH with H2 addition could be attributed to the reduction in acetylene and propargyl concentrations, and reduced H-abstraction rates, which reduced the availability of active sites for PAH growth. The proposed experimental methodology for PAH measurements can be readily applied to any fuel mixtures.

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“…The OH fluorescence is observed in a bandwidth of 305-320 nm collected using an intensified CCD camera fitted with an appropriate optical filter. For the characterization of flame in terms of PAH, Kazuhiro et al [42] used PAH-LIF to visualize it by forming a thin laser sheet of thickness 400 µm for 2D imaging at an excitation wavelength of 283 nm. A narrow band-pass filter (FWHM = 10 nm) of central wavelength 450 nm was used to define the emission band.…”

Section: Pah-lif and Oh-lif Imagingmentioning

confidence: 99%

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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Reductions of PAH and Soot by Center Air Injection

Cited by 5 publications

References 20 publications

Application of FRAME for Simultaneous LIF and LII Imaging in Sooting Flames Using a Single Camera

Application of FRAME for Simultaneous LIF and LII Imaging in Sooting Flames Using a Single Camera

Study of polycyclic aromatic hydrocarbons (PAHs) in hydrogen-enriched methane diffusion flames

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

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