Experimental observations of voidage distribution around bubbles in a fluidized bed

Yates, Y.G.; Cheesman, David; Sergeev, Yu. A.

doi:10.1016/0009-2509(94)80073-1

Cited by 73 publications

(45 citation statements)

References 11 publications

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“…Since, this is not the case, it does not appear that there is any extra interstitial gas available, at least far from the bubble. This leads credence to the observations of Yates et al (1994), that the missing gas is confined to regions near the bubble. shows an expanded view of the trzce eom a singIe bubble that passes directly in front of the centerline probe.…”

Section: 28)supporting

confidence: 86%

Particle pressures in fluidized beds. Final report

Campbell¹,

Rahman²,

Chen³

1996

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Section: 28)supporting

confidence: 86%

Particle pressures in fluidized beds. Final report

Campbell¹,

Rahman²,

Chen³

1996

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“…Two previous studies using 2D beds can be found: Poletto et al [13] obtained data from a bed fluidized with water and Boerefijn and Ghadiri [14] measured the particle concentration in a jet using backscattering. In a different work, Yates et al [9] measured voidage profiles around bubbles in a 3D fluidized bed using X rays. The experimental conditions and /or the measurement techniques employed in these works are different to the ones used in this paper.…”

Section: Experimental Set-up and Calibrationmentioning

confidence: 99%

“…(1) was obtained assuming radial symmetry for the bubble and for the voidage distribution ε = ε(r). Using X rays in a 3D fluidized bed, Yates et al [9] observed the voidage distribution around a stream of injected bubbles. Buyevich et al [10] fitted the following exponential equation to the experi mental results of Yates et al [9] εðrÞ ε mf 1 ε mf = exp 1:5 r R b 1 ð2Þ…”

Section: Introductionmentioning

confidence: 99%

Voidage distribution around bubbles in a fluidized bed: Influence on throughflow

et al. 2010

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a b s t r a c tIn this work, a new method for measuring void fraction distribution around endogenous bubbles in a 2D fluidized bed is presented. The technique is based on illuminating a transparent wall 2 dimensional bed with diffuse light from the rear and recording the distribution of light that penetrates the bed. The recording is made with a high speed video camera, which gives frames with grey level corresponding to the light penetration and from which the voidage distribution around the bubbles can be determined. In this way, voidage distribution in the region very close to the bubble contour (r/R b ≲ 1.2) is obtained, which was not possible in previous studies due to limitations in spatial resolution. A correlation is proposed for the voidage at the contour of the bubble, with the voidage depending on the radial position and the polar angle ε(r, θ). In addition, the effect of the voidage distribution on the throughflow crossing the bubbles was studied and an increase of 20% was determined for the average bubble geometry of the more than 100 bubbles analysed.

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“…In one such study [14], the X-ray source was pulsed for a period of 1 ms and the pulses synchronised with a video recorder at an equivalent speed of 25 frames/s. Both the radiation source and the detector could be moved vertically relative to the fluidized bed, thus allowing different positions to be examined.…”

Section: Bubbling Fluidized Bedsmentioning

confidence: 99%

“…The wedge is set up vertically in the X-ray beam and the transmitted intensity measured on a range of grey scales from 0 to 225 as a function of the wedge thickness l w . The calibration for the Group B alumina powder used in this study [14] gave an explicit relationship between bed voidage, transmitted intensity and path length l of:…”

Section: Bubbling Fluidized Bedsmentioning

confidence: 99%

X-Ray Analysis of Fluidized Beds and Other Multiphase Systems

Yates

Cheesman

Lettieri

et al. 2002

KONA

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The attenuation of a beam of X-rays as it passes through a body has been used for over 100 years in diagnostic medicine. A more recent application of the technique has been in the study of industrial-type units such as gas-solid f luidized beds, and this paper reviews this application in the analysis of the hydrodynamic features of bubbling and circulating f luidized beds. The measurement of jet penetration into bubbling beds and the study of bubble slurry columns are also considered. The equipment used and its methods of operation are described and the salient results of the more revealing investigations are summarised both from a qualitative and a quantitative viewpoint.

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Experimental observations of voidage distribution around bubbles in a fluidized bed

Cited by 73 publications

References 11 publications

Particle pressures in fluidized beds. Final report

Particle pressures in fluidized beds. Final report

Voidage distribution around bubbles in a fluidized bed: Influence on throughflow

X-Ray Analysis of Fluidized Beds and Other Multiphase Systems

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