Simultaneous particle size and 3D position measurements of pulverized coal flame with digital inline holography

Wu, Yingchun; Wu, Xuecheng; Yao, Longchao; Xue, Zhiliang; Zhou, Hao; Cen, Kefa

doi:10.1016/j.fuel.2017.01.024

Cited by 36 publications

(21 citation statements)

References 45 publications

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“…It is observed that the parent coal and fragments follow the gas flow. In the meantime, the dispersed fragments diffuse slightly and radically along the flow due to thermal, jet expansion, 30 and momentum generated during coal fragmentation. So the four fragments at t 0 + 2 ms are distributed in a broader space with time.…”

Section: Resultsmentioning

confidence: 99%

“…Then the morphology, size, 3D position of coal particle fragments are obtained from the reconstructed image. The high measurement accuracy of z location and particle size have been validated in previous research 30,31 by measuring a fixed tungsten wire with the diameter of 300 μm in flame. The results showed that the fluctuation of measured depth(z) position was up to 500 μm, with a standard deviation of 300 μm.…”

Section: Hologram Formation and Postprocessingmentioning

confidence: 86%

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Primary Fragmentation Behavior Investigation in Pulverized Coal Combustion with High-Speed Digital Inline Holography

Lin

Yao

et al. 2019

Energy Fuels

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Comprehension on the primary fragmentation of coal particles is important in understanding and optimizing practical coal combustion and creating credible combustion models. High-speed digital inline holography (DIH) at 6000 Hz is employed to investigate the primary fragmentation of China Ximeng lignite (90−154 μm) during coal devolatilization. The particle morphologies, 3D trajectories, and size evolutions of the parent coals as well as the corresponding fragments are captured by time-resolved holographic visualization. Three fragmentation modes, fragmentation at the particle center, exfoliation/fragmentation at the outer zone, and a hybrid fragmentation mode of both, are observed in this study. The particle morphologies show distinct appearances under the three different fragmentation modes. It is found that the pressure resulted from the volatile products inside particle under the mode of fragmentation at the particle center will accelerate or decelerate the fragments. Statistical result on particle sizes on the recorded 26 coal particles undergoing fragmentation indicates that small particles formed because of coal fragmentation, which occupy 17.1% in the range of 26−40 μm. It is also concluded that the flame temperature and particle residence time during coal devolatilization have an obvious influence on the possibility of coal fragmentation in the operating condition and target research region. Digital inline holography is demonstrated to be capable of in situ three-dimensional (3D) measurement of particle fragmentation during coal devolatilization.

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Section: Resultsmentioning

confidence: 99%

Section: Hologram Formation and Postprocessingmentioning

confidence: 86%

Primary Fragmentation Behavior Investigation in Pulverized Coal Combustion with High-Speed Digital Inline Holography

Lin

Yao

et al. 2019

Energy Fuels

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“…A resume of literature reveals that various optical measurements methods have been proposed and used in the past in laminar flame speed measurements [9,[31][32][33]. These mainly include flame emission imaging techniques i.e.…”

Section: Experimental Facilitymentioning

confidence: 99%

Laminar flame speed of lignocellulosic biomass-derived oxygenates and blends of gasoline/oxygenates

Rossow

Modica

et al. 2017

Fuel

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“…Furthermore, being an imaging-based measurement, DIH only requires calibration of the pixel resolution using precision target with known dimension, without any other secondary measurements or standardized particle samples. The high level of accuracy and sensitivity provided by DIH has enabled multiple applications, including measurement of snowflakes [36] and droplets [37] in the atmosphere, sediments [38] and oil droplets [39] in oceans, coal particles in flames [40] and bubbles in the wake of a ventilated supercavity [41]. More recently, Kumar et al (2019) demonstrated the versatility of DIH to fully resolve monodisperse droplets generated from a vibrating orifice aerosol generator as well as from polydisperse flat fan sprays [33].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of laser diffraction-based particle size measurements using digital inline holography

Kumar

Zhang

Hogan

et al. 2020

Meas. Sci. Technol.

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The measurements of size distribution of small particles (e.g. dusts, droplets, bubbles, etc) are critical for a broad range of applications in environmental science, public health, industrial manufacturing, etc. Laser diffraction (LD), a widely used method for such applications, depends on model-based inversion with underlying assumptions on particle properties. Furthermore, the presence of sampling biases such as velocity differentials are often overlooked in simple ex-situ calibrations, which introduces as an additional source of error. In contrast, digital inline holography (DIH), a single camera coherent imaging technique, can both measure particle size distributions without the need for a model-based inversion and can directly provide information on the shape characteristics of the particles. In this study, we evaluate the performance of an LD system in characterizing polydisperse droplets produced in a flat fan spray using in-situ DIH based imaging as a reference. The systematic differences in the two techniques are examined. A droplet-trajectory-based correction for the LD-inferred size distributions is proposed to compensate for the observed differences. We validate the correction using NIST standard polydisperse particles undergoing differential settling, and then apply the correction to polydisperse spray droplet measurements. The correction improves agreement between LD and DIH size distributions for droplets over two orders of magnitude, but with LD still underestimating the fraction of droplets at sizes above ∼1 mm. This underestimation is possibly linked to the complex oscillatory and rotational motion of droplets which cannot be faithfully captured by measurement or modelled by the correction algorithm without additional information.

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Simultaneous particle size and 3D position measurements of pulverized coal flame with digital inline holography

Cited by 36 publications

References 45 publications

Primary Fragmentation Behavior Investigation in Pulverized Coal Combustion with High-Speed Digital Inline Holography

Primary Fragmentation Behavior Investigation in Pulverized Coal Combustion with High-Speed Digital Inline Holography

Laminar flame speed of lignocellulosic biomass-derived oxygenates and blends of gasoline/oxygenates

Evaluation of laser diffraction-based particle size measurements using digital inline holography

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