快速床动力学统一模型Ⅳ:介观解析与子模型优化

A Unified Model for Fast Fluidization Dynamics——PartⅣ:Fundamental Refining and Sub-Model Optimization

通过介观机理解析及子模型的优化,对已建立的快速流化床动力学统一模型进行了改进。包括:1)模型参数n和气相速度有效系数F(β)的介观模型确定方法;2)A型噎塞Yang公式摩擦系数的实验再相关;3)Harris团聚物尺寸关联式的无因次重建;4)团聚物空隙率的预报及浓相模型修正。应用所建立的统一模型对垂直并流气-固系统的C型噎塞、快速床提升管上部稀相和下部浓相的固含率、以及向高密度快速床和浓相悬浮上升流的过渡等进行了综合性的预报,并得到文献中数百个不同实验结果很好的验证。

On the basis of the authors＇ previous work, more fundamental refining to the unified model proposed for fast fiuidization dynamics was performed, including 1） mechanistic determination of the model parameter n and the effective velocity factor of dilute phase F（β）, 2） reconstruction of Yang＇s formula for type A chocking, 3） reform of Harris＇s correlation for cluster size, and 4） prediction of cluster voidage and revisions to dense phase model. Then, more strict comprehensive comparisons to experimental data available in literatures regarding to type C choking, the solids holdups for both upper dilute and bottom dense regions, and suspension up-flow were made, which verified transitions to high density fast fluidization and dense the model well.