黏性与非黏性颗粒在流化床中的气泡行为模拟

运用离散单元法对黏性与非黏性D类颗粒在气-固流化床中的气泡行为进行研究,分析了气泡在流化床内的产生、长大过程以及黏性力对气泡产生的影响.结果表明:流化速度将影响气泡的产生,而黏性力的作用将推迟气泡的产生;与非黏性颗粒相比,D类黏性颗粒在流化过程中所产生的气泡尺寸减小,上升速度变慢,气泡周围的压力增大、运动速度减小;另外,气泡周围的压力和颗粒运动速度对黏性力较为敏感.

Simulation of Bubble Behavior of Cohesive and Non-Cohesive Particles in Fluidization

Abstract： The discrete element method (DEM) was applied to study the bubble behavior of type D particles to analyze the formation and the growing up process of the bubble in fluidized bed, and the effect of cohesive forces on bubbles. The results of DEM simulation reveal that the formation of bubbles in fluidized bed is related to fluidizing velocity; the introduction of cohesive force causes the first occurrence of bubbling to shift to a higher fluidizing velocity. Compared with non cohesive particles, cohesive particle fluidization exhibits a smaller bubble size and lower rise velocity. In addition, the pressure and the particle velocity around the bubble are found to be sensitive to the inter-particle force.