ECT Studies of Gas-Solid Fluidized Beds of Different Diameters
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- 作者：Bing Du ; W. Warsito ; and Liang-Shih Fan
- 刊名：Industrial & Engineering Chemistry Research
- 出版年：2005
- 出版时间：July 6, 2005
- 年：2005
- 卷：44
- 期：14
- 页码：5020 - 5030
- 全文大小：510K
- 年卷期：v.44,no.14(July 6, 2005)
- ISSN：1520-5045
文摘
The bed dynamic behavior in three gas-solid fluidized beds, 0.05, 0.1, and 0.3 m in diameters,is studied using the electrical capacitance tomography (ECT). The ECT employs the neuralnetwork multicriteria optimization image reconstruction technique. The time-averaged solidsconcentrations obtained by the ECT are generally in good agreement with those obtained bythe optical fiber probe. The 0.1 m ID fluidized bed exhibits the spiral motion of rising bubblesin the bubbling regime. However, for the 0.3 m ID fluidized bed, more than one spiral motion ofbubble swarms is observed in the bubbling regime. The small fluidized bed exhibits the round-nosed slug motion. The ECT studies reveal a radial symmetry of the time-averaged solidsconcentration distribution for the turbulent regime. Furthermore, the ECT provides the time-averaged and transient properties of the bubble/void phase and the emulsion phase. For a largefluidized bed, the standard deviations of the fluctuations of the cross-sectional averaged solidsconcentration, bubble/void phase fraction, and solids concentration in the emulsion phase allpeak at the transition velocity from the bubbling to the turbulent regimes, Uc. For a smallfluidized bed, the quantities of these variables peak at the onset to the slugging regime, decreasein the slugging regime, and then level off in the turbulent regime as the gas velocity increases.