Abstract The characteristics of bubble behaviors during powder discharge process in a two-dimensional aerated hopper were studied by a high-speed camera system. The experimental results show that there are three typical discharge states with the rise of the aeration gas velocity. Correspondingly, three critical aeration gas velocities were all tested including the minimum bubbling, the maximum discharge rate and the minimum bubbling for downward moving to the outlet. The downward moving bubble formation frequency increases with the growth of gas velocity, and its proportion finally stabilizes at about 90%. This tendency is similar with that of the discharge rate. Resultantly, the bubble formed in the powder bed can promote the discharge by provide the interstitial gas to the powder bed, but plays a negative role as it gets larger and substantially moves downward.

中文翻译：

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二维曝气料斗气泡下移出料特性试验研究

摘要 利用高速摄像系统研究了二维充气料斗出粉过程中气泡行为特征。实验结果表明，随着曝气气速的升高，存在三种典型的放电状态。相应地，测试了三个临界曝气气体速度，包括最小鼓泡、最大排放速率和向下移动到出口的最小鼓泡。向下运动的气泡形成频率随着气体速度的增加而增加，其比例最终稳定在90%左右。这种趋势与放电率的趋势相似。结果，在粉末床中形成的气泡可以通过向粉末床提供间隙气体来促进放电，