Development and Validation of Evaluation Methods for 3D Flame Propagation Speed of Turbulent Non-premixed Edge Flames via Tomographic Chemiluminescence

Chi, Yeqing; Lei, Qingchun; Song, Erzhuang; Fan, Wei; Yu, Sha

doi:10.1007/s10494-021-00285-8

Cited by 10 publications

(3 citation statements)

References 47 publications

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“…Band-pass filtered measurement, therefore, can only be used without correction to measure the relative integral intensity of the intermediate radicals that is proportional to an integral heat release rate. This type of measurement has been carried out for thermoacoustic stability analysis in nonpremixed flames − and distributed flames , in different studies. Furthermore, the ratio OH*/CH* is reported to be employed in the determination of the local equivalence ratio in both premixed and nonpremixed flames. ,, In this study, OH* chemiluminescence is measured by a photomultiplier tube module (PMT), model H10722–110, manufactured by Hamamatsu Photonics UK Ltd.…”

Section: Methodsmentioning

confidence: 99%

Time Series and Spectral Analysis of Thermoacoustic Oscillations for Propane-Oxyfuel Combustion in a Swirl-Stabilized, Nonpremixed Combustor

Talal,

Abubakar,

Shakeel

et al. 2023

ACS Omega

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In this study, the time series data for sound pressure and heat release fluctuations were analyzed to establish the stability window of the propane-oxyflames under different operating conditions. The CO2 dilution level and the combustor power density were varied at a fixed global equivalence ratio to investigate the thermoacoustic instability of the flames. The phase difference between the fluctuations and the instantaneous Rayleigh index reveals whether the heat release and pressure fluctuations are coupled, which can result in the amplification of the sound pressure fluctuations. Results showed a negative Rayleigh index and uncoupled fluctuations at low (<40%) and high (>60%) CO2 dilution with coupled fluctuations and sound pressure amplification at intermediate CO2 dilution levels. A peak of varying magnitude appeared in the frequency domain at 465 Hz for both the heat release and pressure fluctuations in the coupled mode. The Strouhal number at different CO2 concentrations revealed a range of vortex-shedding frequencies (300–1000 Hz), suggesting that the coupled mode is vortex-induced. Phase space reconstruction for the sound pressure fluctuations was carried out and it is observed that although the pressure fluctuations are amplified in the coupled mode, limit cycle amplitudes have not been reached. The recorded coupling and uncoupling of the oscillations associated with flame-vortex interactions at certain CO2 concentrations provides a valuable insight on the combustor’s dynamics and toward the development of nonpremixed-oxy-flames combustors.

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Section: Methodsmentioning

confidence: 99%

Time Series and Spectral Analysis of Thermoacoustic Oscillations for Propane-Oxyfuel Combustion in a Swirl-Stabilized, Nonpremixed Combustor

Talal,

Abubakar,

Shakeel

et al. 2023

ACS Omega

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“…The azimuth angles of FBE inlets occupy the range of 0 • -180 • as an ordinary arrangement in practical CT reconstructions [34][35][36]. Figure 6 shows the projections of a turbulent flame, generated by setting the flow rate of ethylene and air as 0.1 and 10.6 standard liters per minute, respectively.…”

Section: Practical Flame Reconstruction In Optical Engine Cylindermentioning

confidence: 99%

Volumetric flame reconstructions in an optical engine cylinder involving refraction and blockage

Gao

Ling

et al. 2023

Meas. Sci. Technol.

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Practical applications of computed tomography (CT) in optical engines require an advanced algorithm that can correct the light refraction through optical windows and reconstruct the 3D signal field partially blocked by structural obstacles. In this work, an advanced CT algorithm is designed for optical engines to simultaneously eliminate the imaging distortion by refraction and to diminish the reconstruction error by partial signal blocking. By combining the pinhole model and Snell’s law, the ray-tracings from discretized 3D voxels in the measurement domain to 2D pixels on the imaging planes are accurately calculated, which restores the distortion on recorded projections. Besides, by deciding the locations and numbers of voxels that actually participate in iterative CT calculation, the iterative update process of voxel intensity becomes independent of the blocked rays, which reduces the reconstruction error. The algorithm is then numerically validated by reconstructing a simulated signal phantom inside an optical cylinder with a lightproof obstacle between the phantom and one recording camera, which imitates the refraction and blocking conditions in practical optical engines. Moreover, experimental demonstration is performed by reconstructing practical premixed flame inside optical engines. Both the simulation and the experiment present significantly enhanced flame chemiluminescence reconstruction by applying the optimized CT algorithm compared to the original algorithm utilized in open-space applications.

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“…Numerical and experimental validations on the turbulent jet flame were conducted. Meanwhile, the relationship between the flame curvature and the propagation speed was analyzed (Chi et al, 2021). Recently, Liu et al (2021b) concentrated on the influence of the external direct current electric field on the propagation speed of swirl flames.…”

Section: Flame Propagation Speed Measurementmentioning

confidence: 99%

A Survey for 3D Flame Chemiluminescence Tomography: Theory, Algorithms, and Applications

Jin

Situ

2022

Front. Photon.

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Combustion diagnostics play an essential role in energy engineering, transportation, and aerospace industries, which has great potential in combustion efficiency improvement and polluting emission control. The three-dimensional (3D) visualization of the combustion field and the measurement of key physical parameters such as temperature, species concentration, and velocity during the combustion process are important topics in the field of combustion diagnostics. Benefiting from the non-contact and non-intrusive advantages of the optical detection method as well as the advantages of the 3D full-field measurement of the measured field by computational tomography, flame chemiluminescence tomography (FCT) has the ability to realize non-intrusive and instantaneous 3D quantitative measurement and 3D full-field visualization of key physical parameters in the combustion process, which has crucial research significance in combustion diagnostics. In this study, we review the progress of FCT technique. First, we provide an extensive review of practical applications of FCT in state-of-the-art combustion diagnostics and research. Then, the basic concepts and mathematical theory of FCT are elaborated. Finally, we introduce the conventional reconstruction algorithm and proceed to more popular artificial intelligence-based algorithms.

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Development and Validation of Evaluation Methods for 3D Flame Propagation Speed of Turbulent Non-premixed Edge Flames via Tomographic Chemiluminescence

Cited by 10 publications

References 47 publications

Time Series and Spectral Analysis of Thermoacoustic Oscillations for Propane-Oxyfuel Combustion in a Swirl-Stabilized, Nonpremixed Combustor

Time Series and Spectral Analysis of Thermoacoustic Oscillations for Propane-Oxyfuel Combustion in a Swirl-Stabilized, Nonpremixed Combustor

Volumetric flame reconstructions in an optical engine cylinder involving refraction and blockage

A Survey for 3D Flame Chemiluminescence Tomography: Theory, Algorithms, and Applications

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