Abstract Flow pattern of cohesive particles in gas-solid fluidized bed is complex, and particles in different regions exhibit various flow patterns. Characterization methods in literatures are deficient in detecting local motions of particles. In this work, particle motions distribution along the axial direction was investigated by acoustic emission detection and pressure fluctuation. The axial distribution of particle motions proved the “stratified fluidization” of cohesive particles and further investigation showed that the stratified fluidization was affected by both the superficial gas velocity and the initial height-to-diameter ratio (H0/D). Increasing the operating gas velocity, the fluidization of the fluidized bed with a relatively low H0/D changed from fixed bed with stable channeling to the two-layer stratified fluidization consisted of the fixed bed layer in the lower part and the bubbling fluidized bed layer in the upper part. While for the fluidized bed with a large H0/D, the fluidization transmitted from fixed bed with unstable channeling to two-layer stratified fluidization, then to multi-layer stratified fluidization with an inflatable fluidized bed layer appeared above the bubbling bed layer. Moreover, a flow pattern map of the fluidization of cohesive particles was established which could show guidance for the selection of optimized operation conditions for fluidization of cohesive particles.

中文翻译：

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通过粒子运动的轴向分布表征气固流化床中粘性粒子的流动模式

摘要 气固流化床中粘性颗粒的流动形态复杂，不同区域的颗粒表现出不同的流动形态。文献中的表征方法在检测粒子的局部运动方面存在不足。在这项工作中，通过声发射检测和压力波动研究了沿轴向的粒子运动分布。颗粒运动的轴向分布证明了粘性颗粒的“分层流化”，进一步研究表明分层流化受表观气速和初始高径比（H0/D）的影响。增加操作气体速度，H0/D较低的流化床流化由稳定窜流的固定床转变为下部固定床层和上部鼓泡流化床层的两层分层流化。而对于大H0/D的流化床，流化从不稳定窜流的固定床过渡到两层分层流化，再到鼓泡床层上方出现充气流化床层的多层分层流化。此外，还建立了粘性粒子流化的流型图，可为粘性粒子流化优化操作条件的选择提供指导。而对于大H0/D的流化床，流化从不稳定窜流的固定床过渡到两层分层流化，再到鼓泡床层上方出现充气流化床层的多层分层流化。此外，还建立了粘性粒子流化的流型图，可为粘性粒子流化优化操作条件的选择提供指导。而对于大H0/D的流化床，流化从不稳定窜流的固定床过渡到两层分层流化，再到鼓泡床层上方出现充气流化床层的多层分层流化。此外，还建立了粘性粒子流化的流型图，可为粘性粒子流化优化操作条件的选择提供指导。