双组分颗粒鼓泡流化床内气泡形状参数

在二维双组分鼓泡床实验装置上,采用高速摄像技术,对床内气泡的形状特性进行了研究,考察了不同形状气泡在床内的轴径向分布,探索了颗粒组成和操作气速对气泡形状的影响。结果表明:不同形状的气泡在鼓泡床内呈正态分布,球形度较好的气泡主要分布于床层底部和壁面附近,而细长的气泡则主要集中于床层中心区域。随着气体速率的增加,气泡的球形度和宽纵比降低,气泡形状趋于细长和不规则;随着重组分增加,气泡的球形度增大而宽纵比减小。双组分颗粒鼓泡流化床内气泡球形度的概率密度较单组分的分布更宽,而宽纵比的概率密度分布与添加的颗粒密度有关。

Bubble Shape Parameters of the Bubbling Fluidized Bed with Binary Particles

The characteristics of the bubble shape were investigated in a 2D fluidized bed with binary particles using digital image analysis technology. The distribution of the bubble shapes in the whole bed was investigated, and the effects of particle composition and gas velocity on the bubble shape were also investigated. The results showed that the parameters of bubble shape were the normal distribution in the bubbling bed. The spherical shape bubbles were mainly distributed in the bottom and the region near the wall, while the slender bubbles were mainly concentrated in the central region of the bed. With the increase of the gas velocity, the bubbleshape factor and bubble aspect ratio decreased, and the bubble shape tended to be slender and irregular. The bubble shape factor increased and bubble aspect ratio decreased with the increase of heavy component. The probability density distribution of bubbleshape factor in the binary dispersed fluidized bed was wider than that in the mono-dispersed fluidized bed, while probability density distribution of the bubble aspect ratio was related to the density of the added second component.