催化剂颗粒流的基本方程及其应用(Ⅱ)

BASIC EQUATIONS AND APPLICATIONS OF CATALYST PARTICLES FLOW(Ⅱ)

本文将催化剂颗粒流的基本方程应用到套管流动、立管流动和平行平板间的流动当中,求出了它们的极限应力解,绘制了主应力谱图和滑移线谱图;讨论了这些流动系统中颗粒流动的"块状"流动机制;提出了颗粒流动系统中的层流和湍流两种流动形态及其判别准则(f/a·Hs/R).另外,文章在分析了催化剂浅床流动规律的基础上。从理论上解释了"架桥"和反向压力梯度现象,并提出了应力增长函数的概念及其计算公式。这些结果对正确地设计和操作颗粒流动系统和移动床以及及时地排除所出现的故障提供了方法,

Applying the basic equations for catalyst particles flow to concentric pipe flow,standpipe flow and flow between parallel flats,this paper resol- ves the distribution of maximum stress in catalyst particles bulk and derives the maximum stress in concentric pipe flow,standpipe flow and flow bet- ween parallel flats.Also,we have drawn the main stress pedigrees and slid- ing line pedigrees of catalyst particles bulk in them.By means of these pedi grees,the author discusses the'bulk state'flow mechanism on particles flow in these flow systems;presents the two flow forms of this particles flow system,and therefore gives the variation criterion number(flA.Ns/ R)of the flow form. Based on the analysis of flow patterns of the shallow bed,this paper explains the appearance of'Bridging'and anti-grade on pressure theoreti- cally,and gives an equation for'Bridging'equilibrium arch.We have also obtained the increasing stress function and its formula.These results can provide effective methods for the design and operation of particles flow sys- tems and moving bed,and method for eliminating breakdown.