高密度浓相流化床中气泡的兼并与分裂特性

利用先进的高速动态分析系统对二维床中气泡的行为进行了研究，通过对所拍摄图象的分析处理．得到了不同介质流化床内形成的气泡形状、大小、聚并及分裂的基本规律和特点．实验研究表明．气泡的兼并主要是两气泡问的合并、被合并气泡总是从气泡的尾涡区曳入气泡；气泡分裂主要发生在操作气速较大或大气泡中，是由于其顶部粒子流(或“剪切流”)的侵入造成的；操作气速较低，粒度、密度较大粒子形成的流化床更易于造成气泡的湮灭。

The bubble behaviors in fluidized bed with dense solid-rich phase

Bubble behaviors in the gas-solid two dimension fluidized bed were investigated using the advanced high-speed video camera. By analyzing the recorded images, basic rules and characteristics of bubbles in the shape, size, rising velocity, coalescence and splitting were gained in fluidized beds with different dense medium. The results showed that the bubble coalescence was mainly occurring between two bubbles, the coalescenced bubble always goes into the leading bubble from its wake. The break of bubbles happen mainly at the higher gas velocity or in the bigger bubble, which is caused by the particles-flow in the roof of bubble. The bubble was annihilated easily at lower gas velocity in a fluidized bed with a higher density and coarser particles.