Immersion Tomography of a Gas–Liquid Medium in a Granular Bed

Покусаев, Б. Г.; Karlov, S. P.; Shreĭber, I. R.

doi:10.1023/b:tfce.0000014382.41730.4c

Cited by 9 publications

(8 citation statements)

References 6 publications

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“…In summary, the MR data clearly support the results of previous workers, in that while some gas remains trapped within the bed due to capillary forces, the remaining gas rises through the bed as discrete bubbles (Bordas et al, 2006, Pokusaev et al, 2004a. Combining the results shown in Fig.…”

Section: Resultssupporting

confidence: 90%

Characterising gas behaviour during gas–liquid co-current up-flow in packed beds using magnetic resonance imaging

Collins

Sederman

Gladden

et al. 2017

Chemical Engineering Science

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Magnetic resonance (MR) imaging techniques have been used to study gas phase dynamics during co-current up-flow in a column of inner diameter 43 mm, packed with spherical nonporous elements of diameters of 1.8, 3 and 5 mm. MR measurements of gas holdup , bubblesize distribution, and bubble-rise velocities were made as a function of flow rate and packing size. Gas and liquid flow rates were studied in the range of 20-250 cm 3 s-1 and 0-200 cm 3 min-1 , respectively. The gas holdup within the beds was found to increase with gas flow rate, while decreasing with increasing packing size and to a lesser extent with increasing liquid flow rate. The gas holdup can be separated into a dynamic gas holdup , only weakly dependent on packing size and associated with bubbles rising up the bed, and a 'static' holdup which refers to locations within the bed associated with temporally-invariant gas holdup , over the measurement times of 512 s, associated either with gas trapped within the void structure of the bed or with gas channels within the bed. This 'static' gas holdup is strongly dependent on packing size, showing an increase with decreasing packing size. The dynamic gas holdup is comprised of small bubbles-of order of the packing size-which have rise velocities of 10-40 mm s-1 and which move between the packing elements within the bed, along with much larger bubbles, or agglomerates of bubbles, which move with higher rise velocities (100-300 mm s-1). These 'larger' bubbles, which may exist as streams of smaller bubbles or 'amoeboid' bubbles, behave as a single large bubble in terms of the observed high rise velocity. Elongation of the bubbles in the direction of flow was observed for all packings.

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Section: Resultssupporting

confidence: 90%

Characterising gas behaviour during gas–liquid co-current up-flow in packed beds using magnetic resonance imaging

Collins

Sederman

Gladden

et al. 2017

Chemical Engineering Science

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“…Preliminary experiments, which are described elsewhere [1], showed that bubbles rose in a flooded granular bed at velocities 1.5-4 times slower than in a free liquid volume. Experiments in the granular beds also indicated the existence of significant transverse velocity components in bubbles.…”

Section: Theoretical Analysismentioning

confidence: 99%

“…The creation of physical and computational models and methods is limited by the unobtainability of visual observations of phase interactions in such flows. Immersion tomography of a gas-liquid medium in a granular bed, a recently developed technique, provides a new means for investigating the hydrodynamics in this type of object [1]. The essence of the immersion visualization technique, in this case, consists of choosing a liquid with a refractive index practically coinciding with the refractive index of the transparent particles of the packing: as a result, the flooded packing becomes an optically homogeneous transparent object in which bubble movement can be observed in any projection.…”

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confidence: 99%

“…A capillary used to feed gas microvolumes in order to create bubbles could be positioned either inside the packing or below it in the free liquid layer. The scheme and description of the experimental setup are found elsewhere [1]. The basic change in the measuring scheme was the use of a Lepton digital computer system (Zelenograd, Russia) as the image recorder.…”

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Immersion tomographic study of the motion of bubbles in a flooded granular bed

Покусаев

Казенин

Karlov

2004

Theor Found Chem Eng

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The microstructure and dynamics of two-phase gasliquid flows in packings and granular beds remain a challenging problem in several fields of advanced engineering, such as chemical technology, the power industry, and petroleum and gas production. The creation of physical and computational models and methods is limited by the unobtainability of visual observations of phase interactions in such flows. Immersion tomography of a gas-liquid medium in a granular bed, a recently developed technique, provides a new means for investigating the hydrodynamics in this type of object [1]. The essence of the immersion visualization technique, in this case, consists of choosing a liquid with a refractive index practically coinciding with the refractive index of the transparent particles of the packing: as a result, the flooded packing becomes an optically homogeneous transparent object in which bubble movement can be observed in any projection. This movement, which depends on the interaction of a bubble with packing elements, is three-dimensional and very complex. For three-dimensional reconstruction of the bubble trajectory, the familiar methods of optimal tomography were used [2]: an object is illuminated in various directions, and optical-parameter distribution in the bulk of the probed object is reconstructed.The granular bed was modeled by a packing of K8 glass beads with a refractive index of 1.51. The liquid used was a solution of α -monobromonaphthaline with methylene iodide in n -decane. The immersion liquid was supplied by the All-Russian Research Institute of Physical Technical and Radio Engineering Measurements of the State Standard Office of the Russian Federation (Gosstandart). Required for the calculations were the following properties of the mixture: density ρ = 990 kg/m 3 , dynamic viscosity µ = 3.5 × 10 -3 Pa s, and surface tension coefficient σ = 3.5 × 10 -2 N/m. Beads with a diameter of d p = 6 × 10 -3 m in the cell were packed in ten layers in the vertical direction and four and eight layers in the transverse directions. However, in most of the experiments, the packing consisted of beads with a diameter of d p = 3 × 10 -3 m with an approximately doubled number of layers in all directions. A capillary used to feed gas microvolumes in order to create bubbles could be positioned either inside the packing or below it in the free liquid layer. The scheme and description of the experimental setup are found elsewhere [1]. The basic change in the measuring scheme was the use of a Lepton digital computer system (Zelenograd, Russia) as the image recorder. This avoided the use of a stroboscopic system and improved image quality. THEORETICAL ANALYSISPreliminary experiments, which are described elsewhere [1], showed that bubbles rose in a flooded granular bed at velocities 1.5-4 times slower than in a free liquid volume. Experiments in the granular beds also indicated the existence of significant transverse velocity components in bubbles. Therefore, roughly, we may regard a flooded granular bed as a highly viscous disper...

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“…There are many applications of light, including making darkness brighter, medical diagnoses, scanning, jewellery, pointers and many more [1][2][3]. From the application (product), the user normally knows that only fix the application of lights from the product produced in the market.…”

Section: 10 Introductionmentioning

confidence: 99%

Study of the Effect of Brightness After Penetration of Light from a Lens

et al. 2013

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There are many types of component that are able to produce light and the light is produced based on the angle and wavelength of the lens. Light penetration depends on the type of material used. The tests are done using basic electronic components which are able to produce light including the light emitting diode (LED), laser and infrared source. From the component, there are two types of light line, one with an angle and one without. It is known that the laser only produces a straight line light while the angle and thickness of light from both the LED, and infrared source increase with distance. The results show that the different types of light must use different types of lenses and they are suitable for use with all light properties.

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Immersion Tomography of a Gas–Liquid Medium in a Granular Bed

Cited by 9 publications

References 6 publications

Characterising gas behaviour during gas–liquid co-current up-flow in packed beds using magnetic resonance imaging

Characterising gas behaviour during gas–liquid co-current up-flow in packed beds using magnetic resonance imaging

Immersion tomographic study of the motion of bubbles in a flooded granular bed

Study of the Effect of Brightness After Penetration of Light from a Lens

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