Spatially and temporally resolved laser/optical diagnostics of combustion processes: From fundamentals to practical applications

Aldén, Marcus

doi:10.1016/j.proci.2022.06.020

Cited by 25 publications

(5 citation statements)

References 241 publications

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“…As stated earlier, there are unnoticeable losses in terms of spatial resolution using a single camera and it is consistent with all configurations applied for flame studies. However, this is only true for factors such as the higher spatial frequency of the modulation (i.e., the lp/mm of the ruling) and the size and order of the low-pass filter used in the spatial lock-in algorithm [16,22].…”

Section: Discussionmentioning

confidence: 99%

“…Frequency Recognition Algorithm for Multiple Exposures (FRAME) is an established technique to reduce stay light contribution while measuring multiple species in a snapshot using a single camera [16,[20][21][22][23]. It works on exciting the flame species using more than one coded laser illumination for probing multiple species in flames in a snapshot.…”

Section: Introductionmentioning

confidence: 99%

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Comparison between Different Optical Configurations of Active-FRAME Setup in Multispectral Imaging of Flames

Chorey,

Boggavarapu,

Deshmukh

et al. 2024

Photonics

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Snapshot multispectral imaging of chemical species in the flame is essential for improved understanding of the combustion process. In this article, we investigate the different configurations of a structured laser sheet-based multispectral imaging approach called the Frequency Recognition Algorithm for Multiple Exposures (FRAME). Using FRAME, a snapshot of Laser-Induced Fluorescence (LIF) of Polycyclic Aromatic Hydrocarbons (PAH) excited by 283.5 nm laser and Laser-Induced Incandescence (LII) of soot particles excited by 532 nm laser are acquired simultaneously on a single FRAME image. A laminar diffusion flame of acetylene produced by a Gülder burner is used for the experiments. The standard FRAME approach is based on creating two spatially modulated laser sheets and arranging them in a cross-patterned configuration (X). However, the effect of using different configurations (angles) of the two laser sheets on the multispectral planar imaging of the flame has not yet been studied. Therefore, we have compared the FRAME approach in four different configurations while keeping the same flame conditions. First, we have compared the relation between laser fluence and LII signals with and without spatial modulation of the 532 nm laser sheet and found that both detections follow the same curve. When comparing the maps of flame species reconstructed from the standard FRAME configuration and other configurations, there are some dissimilarities. These differences are attributed to minor changes in the imaging plane, optical alignment, laser path length, different modulation frequencies of the laser sheet, laser extinction, laser fluence, etc.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Comparison between Different Optical Configurations of Active-FRAME Setup in Multispectral Imaging of Flames

Chorey,

Boggavarapu,

Deshmukh

et al. 2024

Photonics

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“…As discussed in section 1.1, oxy-fuel and recyclable iron combustion have great potential to decarbonize electricity generation but raise plenty of scientific questions. Nonintrusive optical diagnostics are powerful tools that aid understanding and help answer these questions [21,22]. This review summarizes optical diagnostics for solid fuel combustion at the particle level, which requires that the particle's location and/or size is spatially resolved.…”

Section: Scope Of This Reviewmentioning

confidence: 99%

Particle-resolved optical diagnostics of solid fuel combustion for clean power generation: a review

Li,

Geschwindner,

Dreizler

et al. 2023

Meas. Sci. Technol.

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Chemical energy carriers are crucial for addressing challenges that arise from the time lag, large distances, and temporal fluctuations in renewable energy production, which lead to unbalanced energy production and demand. However, the thermochemical utilization of chemical energy carriers such as solid fuels must be widely decarbonized to achieve a climate-neutral circular economy, despite remaining important for reliable electricity generation and stable economics. To accomplish this, extensive fundamental research is required to understand the underlying chemical and physical processes that can potentially be realized on an industrial scale. This paper reviews optical diagnostics used for particle-level combustion studies for clean power generation applications. Specifically, we focus on particle-resolved optical experiments for oxy-fuel coal combustion, biomass combustion, and utilization of iron in a regenerative oxidation-reduction scheme. We summarize previous studies categorized by the type of fuels, used reactors, investigated parameters, and experimental methodology. To provide a shared understanding, phenomenological aspects of the multistage combustion process at the particle level are outlined using examples of bituminous coal and iron particle burning in hot gas, respectively. A selection of experimental studies is highlighted, with a particular methodological focus on the measurement of relevant quantities at the particle level. These representative examples address relevant parameters, including particle number density, particle size and shape, surface temperature, ignition and combustion time, gas flame structure, gas temperature and species, nanoparticle formation, gas velocity, and particle dynamics. Finally, open issues and unsolved problems that require further effort to improve diagnostics for solid fuel combustion studies are discussed.

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“…Combustion research relies upon the measurements of scalar properties affecting the structure and composition of flame processes that determine phenomena such as stability, efficiency, and airborne emissions. Optical diagnostic techniques such as planar laser-induced fluorescence utilize laser to excite species of interest on a 2D plane in the flame, allowing signal to be captured on digital images to yield quantitative information [1]. In contrast, chemiluminescence (CL) imaging is a simpler, non-intrusive optical technique that does not require lasers and it has been used for over half a century to study combustion [2,3].…”

Section: Introductionmentioning

confidence: 99%

Spatially resolved chemiluminescence imaging of multiple combustion species using a single high-speed camera

James,

Agrawal

2023

Meas. Sci. Technol.

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Simultaneous chemiluminescence imaging of multiple chemical species in unsteady and/or turbulent combustion environments requires multiple high-speed camera/intensifier systems which can be cost prohibitive. This study presents a novel optical configuration for simultaneous, spatially resolved chemiluminescence imaging of two species using a single high-speed camera. The superiority of the technique over existing approaches is demonstrated via a series of experiments in a methane fueled McKenna burner operated at steady and unsteady conditions. Results demonstrate capabilities of the present system to provide spatially resolved measurements of hydroxyl (OH*) and methylidyne (CH*) species without parallax or path length errors in different flame configurations.

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Spatially and temporally resolved laser/optical diagnostics of combustion processes: From fundamentals to practical applications

Cited by 25 publications

References 241 publications

Comparison between Different Optical Configurations of Active-FRAME Setup in Multispectral Imaging of Flames

Comparison between Different Optical Configurations of Active-FRAME Setup in Multispectral Imaging of Flames

Particle-resolved optical diagnostics of solid fuel combustion for clean power generation: a review

Spatially resolved chemiluminescence imaging of multiple combustion species using a single high-speed camera

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