Online continuous measurement of the size distribution of pneumatically conveyed particles by acoustic emission methods

Hu, Yonghui; Qian, Xiangchen; Huang, Xiaobin; Gao, Le; Yan, Yong

doi:10.1016/j.flowmeasinst.2014.07.002

Cited by 15 publications

(9 citation statements)

References 18 publications

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“…As a consequence, a more accurate theory is necessary to establish and predict the process. Hu [12] developed an AE-based online particle sizing instrument employing the Hertz theory of contact, and the experimental results were highly consistent with theoretical expectations under limited conditions. However, for increasing solid mass flow rate, the sizing results deviated significantly due to their theoretical assumptions.…”

Section: Introductionsupporting

confidence: 61%

Detection of Pneumatic Conveying by Acoustic Emissions

Liu

et al. 2019

Applied Sciences

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The acoustic emission (AE) method is used in certain industries for the measurement of pneumatic conveying. Instead of the non-intrusive sensors, the comparison of two different intrusive probes in pneumatic conveying is presented in this work, and the AE signals generated by the flow for different particle flow rates and particle sizes were studied. Comparing the distribution of root mean square (RMS) values indicates that the AE signal acquired by a wire mesh probe was more reliable than that from a T-type probe. Limited intrinsic mode functions (IMFs) were extracted from the raw signals by the ensemble empirical mode decomposition (EEMD) algorithm. The characteristics of these signals were analyzed in both the time and frequency domains, and the energies of different IMFs were used to predict the particle mass flow rates, demonstrating a relative error under 10% achieved by the proposed monitoring system. Additionally, the mean squared error contribution fraction, instead of the energy fraction, can predict the particle size.

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Section: Introductionsupporting

confidence: 61%

Detection of Pneumatic Conveying by Acoustic Emissions

Liu

et al. 2019

Applied Sciences

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“…Deflection of the laser beam from the contact mirror, shown in Figs. 2 and 3, was measured by a position sensitive detector (5). We used a quadrant position detector, called the quadrant photodiode, consisting of four identical, square-shaped Si photodiodes placed as to resemble the quadrants divided by the axes in a twodimensional Cartesian coordinate system.…”

Section: Methodsmentioning

confidence: 99%

“…Accurate measurements of the contact time are not only important in the basic studies of contact mechanisms in order to assess the validity of the proposed theory [2], [3], they are also important in a wide range of different applications related to, for example, contact mechanics, tribology, shot peening, wear, erosion, rock falls, military ballistics, measurements of hardness at high strain rates and granular matter research. Due to its linear dependence on the radius, the contact time of spherical particles impacting thick plates is, for instance, a good criterion for their size [4], [5], [6], [7], [8] whereas particle sizing is an important requirement in many areas of industrial processing and manufacture [8]. If the velocity of the particle is known with some uncertainty, the size of the particle can be determined via its impact with another solid more accurately by measuring the contact time than the maximum force [5], [6], [8], because the contact time has a more gentle dependence on the approach velocity as opposed to the maximum force.…”

Section: Introductionmentioning

confidence: 99%

“…Due to its linear dependence on the radius, the contact time of spherical particles impacting thick plates is, for instance, a good criterion for their size [4], [5], [6], [7], [8] whereas particle sizing is an important requirement in many areas of industrial processing and manufacture [8]. If the velocity of the particle is known with some uncertainty, the size of the particle can be determined via its impact with another solid more accurately by measuring the contact time than the maximum force [5], [6], [8], because the contact time has a more gentle dependence on the approach velocity as opposed to the maximum force. A sphere drop on a stationary plate or a block is also often used as a standard acoustic source of ultrasonic waves.…”

Section: Introductionmentioning

confidence: 99%

“…Side-view schematic drawing of the experimental setup. The setup consists of the laser source (1), two convergent lenses (2), electromagnet (3), piezo (PZ) sensor (4), deployed at a distance d from the center of impact, and quadrant photodiode(5)…”

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confidence: 99%

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Optical Detection of Impact Contact Times with a Beam Deflection Probe

2017

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We present an optical detection technique, called the beam deflection probe, to accurately measure contact times of normal-incidence impacts of steel and sapphire spheres with a transparent glass block. It exploits the deformation of the area that is in a mechanical touch during the rebound. The deformation of the surface acts as a dynamic contact mirror. When illuminated by a laser beam, total internal reflection takes place at the contact mirror, the beam is deflected from it, and its angular deflection history is monitored by a quadrant photodiode. A simple threshold-level data processing of the photodiode signals is used to determine the impact duration. It is shown that the shape of the signal is highly dependent on the location of the impact relative to the center of the laser-beam illuminated area while the determination of the contact time does not depend on the impact position. Using an automated ball release mechanism, the contact time of low-velocity impacts was measured for various ball diameters and approach velocities conforming to the Hertz contact theory. The proposed optical detection of contact times supplements the existing measurement techniques and represents the only alternative to the piezoelectric detection when contact times are to be measured on the microsecond scale.

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The screened waveguide for intrusive acoustic emission detection and its application in circulating fluidized bed

et al. 2020

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A screened waveguide with a 90° elbow, which had a rubber surface to reduce noise generations and a steel/air interface to block noise propagations, was designed to measure local particle movements in certain directions. In the riser of circulating fluidized bed, the noise energy only accounted for 2.1% of the total energy received by the waveguide. Besides, the radial acoustic emission energy distribution detected via the waveguide was highly consistent with the radial solid flux distribution measured by the extraction probe. Furthermore, the radial flow patterns in the riser with Geldart D particles were measured under dense phase conveying by this new method, which always demonstrated as core‐annulus flows and the transition points (r/R) increased with decreasing solid–gas ratios.

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Online continuous measurement of the size distribution of pneumatically conveyed particles by acoustic emission methods

Cited by 15 publications

References 18 publications

Detection of Pneumatic Conveying by Acoustic Emissions

Detection of Pneumatic Conveying by Acoustic Emissions

Optical Detection of Impact Contact Times with a Beam Deflection Probe

The screened waveguide for intrusive acoustic emission detection and its application in circulating fluidized bed

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