螺旋导流膜分离器流动特性及其分离性能研究

发布时间：2018-04-09 02:34

本文选题：螺旋导流膜分离器　切入点：浓差极化　出处：《华东理工大学》2015年硕士论文

【摘要】：为抑制膜分离过程中的浓差极化和膜污染现象,强化膜分离过程,拓展膜分离的应用领域,提出了一种新型的膜分离形式——螺旋导流膜分离器。论文首先利用Fluent软件对螺旋导流膜分离器内流体流动特性进行数值模拟研究,分析了其新型的分离机理；然后,对流道结构参数进行优化,并以此为基础搭建了实验装置,研究了新型膜分离器的分离性能；最后,在螺旋导流膜分离器的基础上开发了螺旋流过滤器,实现了其工业运行。论文主要得出如下结论：(1)螺旋导流膜分离器中由于壁面效应引起的角涡流,能较好的抑制部分膜面的微粒上的沉积。内置膜管式螺旋导流膜分离器,主要依靠悬浮液中固液两相的密度差所受的离心力不同来抑制微粒在膜表面上的沉积,适用于分离微粒密度大于液相的、密度差较大悬浮液的分离。而外置膜管式螺旋导流膜分离器不同,由于Dean二次流靠近膜面,能将沉积膜面上的微粒带回主流区,从而减小浓差极化和膜污染现象,所以外置膜管式螺旋导流膜分离器适用于液固两相密度差较小或相近的悬浮液的分离。(2)通过对矩形截面螺旋流的研究,矩形截面螺旋流在De=246左右时候就产生失稳,产生Dean二次流。对于螺旋导流膜分离器,矩形截面螺旋流的截面比在2.5-3.5之间,螺旋升角在10.4°～21.2°为较佳尺寸。(3)操作压力较进料流速更能提高膜渗透通量,而料液浓度的增加会导致膜渗透通量的下降。实验中操作压力均处于膜分离临界压力以下,对于螺旋导流膜分离器的临界压力还有待实验研究。(4)在内置螺旋导流膜分离器基础上,开发了螺旋流过滤器,较好的解决了工业上跨密度悬浮液的分离。
[Abstract]:In order to restrain the concentration polarization and membrane fouling during membrane separation, strengthen the membrane separation process and expand the application field of membrane separation, a new type of membrane separation form-helical diversion membrane separator was proposed.In this paper, the fluid flow characteristics in the helical diversion membrane separator are studied by using Fluent software, and the new separation mechanism is analyzed, then the flow channel structure parameters are optimized, and the experimental device is built.The separation performance of the new membrane separator is studied. Finally, the helical flow filter is developed on the basis of the spiral diversion membrane separator, and the industrial operation of the filter is realized.The main conclusions of this paper are as follows: (1) the angular eddy current caused by wall effect in the spiral film separator can restrain the deposition of particles on the surface of the film.The inner membrane tube spiral diversion membrane separator mainly depends on the different centrifugal force of the density difference between the solid and liquid phases in the suspension to suppress the deposition of the particles on the membrane surface, which is suitable for separating the particles with a density greater than that of the liquid phase.Separation of suspensions with large density difference.Because the secondary flow of Dean is close to the membrane surface, the particles on the deposition surface can be brought back to the main stream, thus reducing the concentration polarization and membrane fouling.Therefore, the outer membrane tube spiral diversion membrane separator is suitable for the separation of suspensions with small or similar liquid-solid phase density. Through the study of the rectangular section helical flow, the rectangular cross section spiral flow produces instability at about the time of De=246.Dean secondary flow is generated.For the helical diversion membrane separator, the cross section ratio of the rectangular section helical flow is between 2.5-3.5, and the spiral rising angle is 10.4 掳or 21.2 掳. The operating pressure can improve the membrane permeation flux more than the feed flow rate.The increase of feed concentration will lead to the decrease of membrane permeation flux.In the experiment, the operating pressure is below the critical pressure of membrane separation. The critical pressure of the spiral diversion membrane separator needs to be studied experimentally. (4) the spiral flow filter is developed on the basis of the built-in spiral diversion membrane separator.The separation of industrial transdensity suspensions is well solved.
【学位授予单位】：华东理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ051.893

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