正方形流化床结构参数改变和内构件强化的数值模拟解析

发布时间：2018-06-18 02:40

本文选题：气液两相流 + 流化床　；参考：《化工进展》2017年06期

【摘要】：借助数值模拟方法分析多功能结构反应器内部的流体力学行为,可以减少放大实验的批次,获知反应器结构关于废水生物处理功能区划的描述。以土建工程便利的正方形流化床为研究对象,通过改变下降区和上升区面积比(A_d/A_r)、环隙过流区和上升区面积比(A_b/A_r)、导流筒与液面距离和导流筒高度比(H_t/H_(dt))3种结构参数,并添加十字型挡板和漏斗型导流板两种内构件,考察各种状态下液速(U_L)和气含率(ε_G)的流体特性响应行为,在实现高效氧传质、节能与短程硝化反硝化方面寻找结构优化和操作条件优化的空间。结果表明:A_d/A_r的改变主要影响液速的分布及其峰值,取1.25;A_b/A_r主要影响流化床底部的液速的大小和方向,取1.2为宜;H_t/H_(dt)主要影响导流筒上方液体受到的有效整流作用,取值1/8。在结构参数优化的基础上,两种内构件对流化床的耦合作用能够满足生化流化床技术对低液速和各生化阶段气含率的需求。结果证明了采用CFD数值模拟可以实现废水处理不同目标体系下反应器功能化开发,结构参数优化和内构件置入的正方形流化床反应器具有强化传质与区域功能化的特征,两个方面的结合可以实现能量高效利用和降低研发成本的目标。
[Abstract]:The numerical simulation method is used to analyze the hydrodynamic behavior in the multi-functional structural reactor, and the batch of the amplification experiment can be reduced. The description of the bioreactor division of the wastewater is described. The square fluidized bed with the convenience of the civil engineering is used as the research object, by changing the area ratio of the descending area and the rise area (A_d/A_r) and the annular gap. 3 structural parameters of the overflow area and the rise area ratio (A_b/A_r), the distance between the diversion tube and the liquid surface and the height ratio of the guide tube (H_t/H_ (DT)), and the two internal components of the cross type baffle and the funnel type guide plate are added to investigate the fluid response behavior of the liquid velocity (U_L) and gas holdup (epsilon _G) in various states, and to achieve high efficiency oxygen mass transfer, energy saving and short range nitrification. The results show that the change of A_d/A_r mainly affects the distribution and peak of the liquid velocity and 1.25; A_b/A_r mainly affects the size and direction of the liquid velocity at the bottom of the fluidized bed, and 1.2 is appropriate; H_t/H_ (DT) mainly affects the effective rectification action of the liquid above the guide tube and the value of 1/8. On the basis of structural parameters optimization, the coupling effect of two internal components in the fluidized bed can meet the requirements of biochemical fluidized bed technology for low liquid speed and gas holdup at various biochemical stages. The results show that the use of CFD numerical simulation can be used to achieve reactive power development, structural parameters optimization and internal component placement in different target systems of wastewater treatment. The square fluidized bed reactor has the characteristics of strengthening mass transfer and regional functionalization. The combination of the two aspects can achieve the goal of efficient utilization of energy and reduction of R & D cost.
【作者单位】：华南理工大学环境与能源学院;江西理工大学建筑与测绘工程学院;工业聚集区污染控制与生态修复教育部重点实验室;广州市市政工程维修处;
【基金】：广东省应用型科技研发专项基金(2015B020235005) 国家自然科学基金(51278199,21406096) 江西省青年科学基金计划(20142BAB213022)项目
【分类号】：TQ051.13;X703

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