基于粉体流变特性表征的气泡行为分析

Analysis of bubble behaviors based on characterization of rheological properties of powders

粉体床层中的气泡行为是工业过程中重要的研究对象。文中以玻璃微珠为实验介质,基于粉体流变仪对粉体流变特性的定量化表征,利用二维单孔鼓泡床层对比研究了不同粉体床层中的气泡运动特性。采用圆形度对气泡形状进行描述,参考水中气泡圆形度预测模型建立了偏差在±20%以内的气泡圆形度预测模型,体现了粉体床层鼓泡过程中的拟流体属性。实验结果表明:粉体流变特性的差异对床层中的气泡行为具有显著影响,当粉体单位通气能增加约29倍时,平均气泡面积降低约25%,速度降低约18%,圆形度增加约36%。研究结果对于粉体床层中复杂的气泡行为研究具有一定的参考价值。

Bubble behaviors in powder beds have received great attention from the industrial and academic community.In this paper,glass beads were selected as experimental materials.Based on the quantitative characterization of powder rheological properties by a powder rheometer,bubble behaviors in different powder beds were compared in a two-dimensional single-hole bed.The bubble shape was described by the circularity.A bubble circularity prediction model was proposed by referring to the bubble circularity prediction model in water,and model deviation was within±20%,indicating the pseudo-fluid property of powders during bubbling process.The experimental results show that powder rheological properties have a significant effect on bubble behaviors.When the unit aeration energy of powders increased by about 29 times,the average bubble area decreased by about 25%,the speed decreased by about 18%and the circularity increased by about 36%.The results can provide useful reference for the study of complex bubble behaviors in powder beds.