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>The Influence of the Distributor Plate on the Bottom Zone of a Fluidized Bed Approaching the Transition from Bubbling to Turbulent Fluidization
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The Influence of the Distributor Plate on the Bottom Zone of a Fluidized Bed Approaching the Transition from Bubbling to Turbulent Fluidization
The dynamics of the bottom zone of a narrow fluidized bed, from bubbling to turbulent regimes, was studied in a cold model of 0.1 m i.d. and 1.3 m high. Tested distributor types were perforated perspex plates, with six different perforation grids, metallic mesh and porous ceramic, with pressures drops ranging from 0.05 to 350 kPa, corresponding to superficial air velocities from 0.1 to 2.3m s-1. Group B silica ballotini, within the range 0.355-0.425 mm, were used as bed material. The experimental data consisted of pressure drop and absolute pressure fluctuating signals, together with visual observations. The bottom zone presented a dynamic condition that produced higher pressure drop values than those expected with the incipient fluidization condition, particularly for the distributor plates with a higher open area. A simple model is used to describe the axial solids distribution and the dynamics characteristics of the voids created in that zone, and an attempt is made to differentiate the bubble voidage from that of the dense phase, with a value of through flow estimated in a systematic way.
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机译:在0.1 m i.d.的冷模型中研究了从沸腾到湍流状态的狭窄流化床底部区域的动力学。和1.3 m高。经测试的分配器类型为穿孔的有机玻璃板,具有六个不同的穿孔网格,金属网和多孔陶瓷,压降范围为0.05至350 kPa,对应的表观风速为0.1至2.3m s-1。将0.355-0.425 mm范围内的B组二氧化硅Ballotini用作床层材料。实验数据包括压降和绝对压力波动信号,以及肉眼观察。底部区域呈现出动态条件,该条件产生的压降值高于初始流化条件下预期的压降值,特别是对于具有较大开口面积的分配器板。使用简单的模型描述轴向固体分布和在该区域中产生的空隙的动力学特性,并尝试将气泡空隙率与密相的空隙率区分开,并通过系统估算通流值道路。
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