Fiber-based endoscopes for 3D combustion measurements: View registration and spatial resolution

Kang, Min-Wook; Wu, Yue; Ma, Lin

doi:10.1016/j.combustflame.2014.06.002

Cited by 46 publications

(22 citation statements)

References 25 publications

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“…The operation of the laser and cameras was synchronized using control electronics. Prior to any measurement, a calibration target was used to determine the orientation and location of the cameras using a view registration program [28,29]. The orientations of camera 1 through 5 were determined to be θ = 270.0°, 311.8°, 341.9°, 73.7° and 111.1°, respectively, with an accuracy estimated to be within 0.5°.…”

Section: Experimental Arrangementmentioning

confidence: 99%

Single-shot volumetric laser induced fluorescence (VLIF) measurements in turbulent flows seeded with iodine

Wu¹,

Xu²,

Lei³

et al. 2015

Opt. Express

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This work reports the experimental demonstration of single-shot visualization of turbulent flows in all three spatial dimensions (3D) based on volumetric laser induced fluorescence (VLIF). The measurements were performed based on the LIF signal of iodine (I 2 ) vapor seeded in the flow. In contrast to established planar LIF (PLIF) technique, the VLIF technique excited the seeded I 2 vapor volumetrically by a thick laser slab. The volumetric LIF signals emitted were then simultaneously collected by a total of five cameras from five different orientations, based on which a 3D tomographic reconstruction was performed to obtain the 3D distribution of the I 2 vapor in the target flow. Single-shot measurements (with a measurement duration of a few ns) were demonstrated in a 50 mm × 50 mm × 50 mm volume with a nominal spatial resolution of 0.42 mm and an actual resolution of ~0.71 mm in all three dimensions (corresponding to a total of 120 × 120 × 120 voxels). 249-256 (1996). 18. M. Zhang, J. Wang, W. Jin, Z. Huang, H. Kobayashi, and L. Ma, "Estimation of 3D flame surface density and global fuel consumption rate from 2D PLIF images of turbulent premixed flame," Combust.

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Section: Experimental Arrangementmentioning

confidence: 99%

Single-shot volumetric laser induced fluorescence (VLIF) measurements in turbulent flows seeded with iodine

Wu¹,

Xu²,

Lei³

et al. 2015

Opt. Express

Self Cite

View full text Add to dashboard Cite

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“…The next step in the experiments was to perform a view registration to determine the orientation and position of all the cameras [31,32] . In the view registration process, a calibration target with known dimensions and patterns was placed at the location where the target flame was expected.…”

Section: Experimental Arrangementmentioning

confidence: 99%

3D flame topography and curvature measurements at 5 kHz on a premixed turbulent Bunsen flame

Lei

et al. 2016

Combustion and Flame

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a b s t r a c tThis work reports the measurements of three-dimensional (3D) flame topography and curvature of a premixed turbulent Bunsen flame at a rate of 5 kHz, using a technique combining chemiluminescence and tomography. Line-of-sight images of chemiluminescence (termed projections ) of the target flame were recorded by six cameras from different orientations simultaneously at 5 kHz. Based on these projections, a tomography algorithm reconstructed the 3D flame structure, based on which 3D curvature was then calculated. Due to the 3D nature of the data, statistics of flame properties can then be extracted both in temporal and spatial domains. Probability density function (PDF) of flame topography was extracted from a series of 3D measurements, and the PDFs of the flame at different spatial locations were examined. Furthermore, the instantaneously measured 3D flame topography also enabled the calculation of 3D flame curvature (or 2D curvature along an arbitrary orientation). The PDFs of curvature in 2D and 3D were then extracted and compared. These results provide quantification of the flame surface shape in 3D (cylindrical, elliptic, or hyperbolic), illustrating the utility of 3D diagnostics to fully resolve the dynamics of turbulent flames.

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“…The object domain in their experiments was 9.5 × 9.5 × 9.5 mm 3 for an object distance of about 200 mm [10], and 6 × 6 × 12 mm 3 for an object distance of about 100 mm [11]. Tomographic inversion by simulated annealing and ART algorithms were used in the computation.…”

Section: Introductionmentioning

confidence: 99%

“…Algorithms such as the algebraic reconstruction technique (ART), combined with cylindrical projections that were nonparallel and perspective corrected, were applied to achieve image reconstructions. Fiber-based endoscopes were used in the 3D-CTC experiments of Ma et al [10][11][12], making the 3D-CTC procedure much more flexible by not requiring direct line-ofsight. Two or more cameras were used in their studies.…”

Section: Introductionmentioning

confidence: 99%

Three-dimensional flame measurements with large field angle

Wang

Zeng

et al. 2017

Opt. Express

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Abstract:A system for three-dimensional computed tomography of chemiluminescence was developed to measure flames over a large field angle. Nine gradient-index rods, with a 9 × 1 endoscope and only one camera are used. Its large field of view, simplicity, and low cost make it attractive for inner flow field diagnostics. To study the bokeh effect caused by the imaging system on reconstruction solutions, fluorescent beads were used to determine the blurring function. Experiments using a steady diffusion flame were conducted to validate the system. Three models, namely the clear-imaging, out-of-focus imaging, and deconvolution models, were utilized. Taking the bokeh effect into account, the results suggest that based on run-times the deconvolution model provides the best reconstruction accuracy without increasing computational time.

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Fiber-based endoscopes for 3D combustion measurements: View registration and spatial resolution

Cited by 46 publications

References 25 publications

Single-shot volumetric laser induced fluorescence (VLIF) measurements in turbulent flows seeded with iodine

Single-shot volumetric laser induced fluorescence (VLIF) measurements in turbulent flows seeded with iodine

3D flame topography and curvature measurements at 5 kHz on a premixed turbulent Bunsen flame

Three-dimensional flame measurements with large field angle

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