A physical model is suggested to explain the occurrence of a shell of varying porosity around a gaseous bubble rising in a fluidized bed. According to the model, this phenomenon is a direct consequence of the necessity to maintain the balance of forces acting on solid particles in the vicinity of th
Measurement of charge distribution around a rising bubble in a 2-D fluidized bed
β Scribed by Aihua Chen; Hsiaotao T. Bi; John R. Grace; Flip Kleijn van Willigen; J. Ruud van Ommen
- Publisher
- American Institute of Chemical Engineers
- Year
- 2005
- Tongue
- English
- Weight
- 685 KB
- Volume
- 52
- Category
- Article
- ISSN
- 0001-1541
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β¦ Synopsis
Abstract
A technique has been developed to determine the charge distribution around single rising bubbles in a twoβdimensional fluidized bed. Four induction probes positioned flush with the outside wall of the column and connected to charge amplifiers record induced charge signals as bubbles pass. The charge distribution surrounding a single bubble is then reconstructed with the assumption that the bubble is symmetrical and that the charge around the bubble remains constant as it rises. The emulsion phase far from the bubble in a twoβdimensional fluidized bed of glass beads was found to be charged negatively and, contrary to our previous assumptions, the charge density decreased gradually toward the bubbleβdense phase interface, with a nearly zero charge density inside the bubble. The wake of the bubble is more negatively charged than the emulsion phase, supporting our previous speculations. Β© 2005 American Institute of Chemical Engineers AIChE J, 2006
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