文档介绍：附录(外文翻译)
外文原文
Homogeneous Fluidization Characteristics of VibratingFluidized Beds
In recent years, there has been growing interest in utilizing mechanicalvibration to improve the performance of a fluidized bed in theprocessing of relatively large particles. The advantages of vibratingfluidized beds (VFB) over conventional fluidized beds include reducedminimal fluidization velocity and fluidization pressure drops, increasedefficiency of gas-solid contact and improved homogeneity and stabilityof the fluidized bed layers. These advantages can be used in drying,cooling, heating, separating, mixing process, etc.
In conventional fluidized beds, the possibility for arising of homoorheterogeneous fluidization is connected directly with the so-calledstability of the fluidized system. Moreover, the theories dealing thestability often examine the behavior of their density micro- stability of the bed density is a subject of focus in the segregationof granular solids. Any large fluctuation in the bed density will resultin a failure of separation in some regions and this leads to a decreasein the total separation efficiency. In developing better separationtechnology, a greater stability of bed layers will be required. A methodfor the classification of granular materials in vibrating fluidized bedshas already been suggested (Zhang et al., 1996; Chen et al., 1993),which is useful in the separation of fine coal and the segregation ofwaste coke-slag mixture. All these technologies use vibration energy toimprove bed homogeneity.
The effects of vibration on fluidization quality are importantfor separation in fluidized beds. However, there have been only fewstudies of the effect of vibration on fluidization homogeneity in theliterature. By analyzing capacitance charts, Morse (1955) suggests thathomogeneity and stability exist only for beds of smaller particles (1–70μm) and high frequencies of vibration (l0–50Hz). By measuring thefluctuations of voidage in space and i