Analyzing threshold velocities for fluidization and pneumatic conveying
Analyzing threshold velocities for fluidization and pneumatic conveying
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DOI：
10.1016/j.ces.2008.04.004
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发表时间：
2008-07
影响因子：
4.7
通讯作者：
H. Kalman;E. Rabinovich
中科院分区：
文献类型：
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作者：
H. Kalman;E. Rabinovich
在以前的工作中，我们已经表明，通过将各种阈值速度定义为修正雷诺数作为修正阿基米德数的函数，可以绘制出广义的主曲线。然后，利用这条曲线，可以很容易地确定各种阈值速度之间的比率。然而，所有的阈值速度都是为单一大小的粒子定义的。本文的目的是展示如何使用阈值速度来设计颗粒-流体系统的粒度分布。该分析为各种工程场景提供了实用的指导，例如选择适当的流化速度以实现最大流化和最小夹带，以及确定气动系统的输送速度。此外，对于表面速度小于跳跃速度的情况，该分析还可用于判断管道底部沉积的颗粒层是静止的还是运动的。
In previous works we have shown that by defining various threshold velocities in terms of the modified Reynolds number as a function of the modified Archimedes number a generalized master-curve can be plotted. Then, using this curve, the ratio between various threshold velocities can be easily determined. However, all the threshold velocities were defined for mono-sized particles. The purpose of this paper is to show how the threshold velocities can be used to design of particle–fluid systems for particle size distribution. The analysis provides practical guides for various engineering scenarios, such as selecting the appropriate fluidization velocity for maximum fluidization and minimum entrainment and determining the conveying velocity in pneumatic systems. In addition, the analysis provides a guide to determine whether the deposited layer of particles at the pipe bottom is stationary or moving, for cases where the superficial velocity is smaller than the saltation velocity.