电渗析器中流场的计算流体力学（CFD）模拟研究

发布时间：2018-04-15 02:04

本文选题：电渗析 + 计算流体力学　；参考：《中国海洋大学》2015年硕士论文

【摘要】：电渗析作为一种应用较早的水处理技术在各个领域发挥着越来越重要的作用。合适的电渗析器组件设计成为解决电渗析面临浓差极化和结垢问题的最佳选择之一。随着CFD技术的不断发展和完善,利用CFD技术来实现对电渗析过程模拟与研究,以及电渗析器组件的设计与优化成为可能。本文通过计算流体力学(CFD)方法,对电渗析器中加入隔板后流动通道中流场进行三维数值模拟,探究隔板构型对流体流动行为的影响。首先讨论了隔板网丝夹角对电渗析过程中流体流动行为的影响。网丝夹角变化时,通过计算和分析流场中压力降、速度云图、剪应力变化趋势等来确定较优化的网丝夹角。结果表明压降与网丝夹角呈指数型关系,流体在流场中湍动会随着网丝夹角的增大而在局部区域有所加强,壁面附近剪切应力随着网丝夹角的增大而增加,综合考虑后,确定最佳的网丝夹角应尽量在80°～900范围内。然后针对布水槽的构型以及隔板长宽比分别进行了模拟研究。结果表明布水槽的长度对压降影响较小,而布水槽宽度对压降影响较明显,考虑了速度云图、剪切应力分布图、速度矢量图以及部分截面速度分布图后,认为布水槽长度一定的情况下,选择较宽的布水槽有利于流体湍动,强化传质过程,本文中选择布水槽宽度为4mmm为宜；隔板长宽比增加会导致压降增大,而从速度矢量图、剪切应力分布图以及部分截面速度分布图,可以看出随着长宽比的增加,流场中湍动也在加强,但是死区范围并不随着长宽比的增加而逐渐减小,因此,实际应用中根据需要选择适宜的长宽比,文中较适宜的隔板长宽比为1：0.52。本文的研究可以使我们了解电渗析器内部流场随隔板构型的变化情况,希望可对电渗析器的设计、优化和改造提供一定的参考,为企业的节能与利润的提高有一定的意义。
[Abstract]:Electrodialysis, as an earlier water treatment technology, is playing a more and more important role in various fields.The design of suitable electrodialysis unit is one of the best choices to solve the problem of concentration polarization and scaling.With the development and perfection of CFD technology, it is possible to use CFD technology to realize the simulation and research of electrodialysis process, as well as the design and optimization of electrodialysis unit.In this paper, the three-dimensional numerical simulation of the flow field in the flow channel after the addition of the diaphragm in the electrodialysis is carried out by means of computational fluid dynamics (CFD) method, and the influence of the configuration of the diaphragm on the flow behavior of the fluid is investigated.The influence of the angle of the mesh wire on the fluid flow during electrodialysis is discussed.When the angle of mesh wire changes, the optimum angle of mesh wire is determined by calculating and analyzing the pressure drop, velocity cloud diagram and shear stress change trend in the flow field.The results show that the pressure drop is exponentially related to the angle of the mesh wire, the turbulence of the fluid in the flow field will be strengthened in the local region with the increase of the angle of the mesh wire, and the shear stress near the wall increases with the increase of the angle of the mesh wire.The optimum angle of mesh should be within the range of 80 掳/ 900 as far as possible.Then, the configuration of the flume and the ratio of length to width of the spacer were simulated.The results show that the length of the flume has little effect on the pressure drop, while the width of the flume has a more obvious effect on the pressure drop. After considering the velocity cloud diagram, shear stress distribution, velocity vector diagram and partial section velocity distribution,It is considered that when the length of the flume is fixed, the wider flume is favorable to the fluid turbulence and the mass transfer process is strengthened. In this paper, the suitable width of the flume is 4mmm, and the increase of the ratio of length to width of the spacer will lead to the increase of the pressure drop, and the velocity vector diagram.It can be seen that the turbulence in the flow field is strengthened with the increase of the aspect ratio, but the dead zone does not decrease with the increase of the aspect ratio.In practical application, the suitable ratio of length to width is chosen according to the need, and the more suitable ratio of length to width of the partition is 1: 0.52in this paper.The research in this paper can make us understand the change of the flow field with the configuration of the diaphragm in the electrodialysis unit. It is hoped that it can provide a certain reference for the design, optimization and transformation of the electrodialysis device, and it will be of certain significance for the enterprise to save energy and improve the profit.
【学位授予单位】：中国海洋大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ028.7

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