A study of flow field and concentration polarization evolution in membrane channels with two-dimensional spacers during water desalination
A study of flow field and concentration polarization evolution in membrane channels with two-dimensional spacers during water desalination
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DOI：
10.1016/j.memsci.2014.11.029
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发表时间：
2015-03-01
影响因子：
9.5
通讯作者：
Dudeck, M.
中科院分区：
文献类型：
--
作者：
Amokrane, M.;Sadaoui, D.;Dudeck, M.
这项研究是一个综合建模的演变（在空间和时间）的流量和浓度场在膜间隔填充通道的水脱盐。这种详细的模型预测是有实际意义的，从而提高理解螺旋缠绕膜（SWM）组件的操作。采用浸没式和锯齿形间隔丝2维配置，因为它们产生SWM模块中遇到的几何流道特征（接触线、流动收缩等）。数值研究，在雷诺数范围内进行典型的脱盐模块，是集中在局部传质系数k和浓差极化，显着影响SWM模块的性能的演变。得到了这些参数的详细定量预测，这些参数与壁面剪应力、静压和渗透通量的变化有关。通过关注膜通道的典型区域（充分捕获不断变化的流动特性），预测平均k值的增加（伴随着浓差极化的减少）与压降的不期望的增加相关;这些相互冲突的要求可以通过选择适当的间隔几何形状来平衡。膜丝接触线对浓差极化的负面影响是有据可查的。从这个角度来看，两个间隔丝配置的评估和未来的研究方向进行了概述。(C)2014爱思唯尔有限公司版权所有。
This study is a step toward integrated modeling of the evolving (in space and time) flow and concentration fields during water desalination in membrane spacer-filled channels. Such detailed model predictions are of practical significance, leading to improved understanding of spiral wound membrane (SWM) module operation. Submerged and zigzag spacer filament 2-dimentional configurations are employed, as they create geometric flow-channel features (contact lines, flow constrictions, etc) encountered in SWM modules. The numerical study, performed in a Reynolds number range typical for desalination modules, is focused on the evolution of local mass transfer coefficient k and concentration polarization, which significantly affect SWM module performance. A detailed quantitative prediction is obtained of these parameters, which are linked to the variation of wall shear stress, static pressure and permeation flux. By focusing on a typical region of the membrane channel (adequately capturing the evolving flow characteristics), it is predicted that increasing average k values (with the concomitant reduction of concentration polarization) are associated with the undesirable increase of pressure drop; these conflicting requirements can be balanced through the selection of appropriate spacer geometry. The negative effect of membrane filament contact lines on concentration polarization is well documented. An assessment is made of the two spacer filament configurations, from this perspective, and directions for future research are outlined. (C) 2014 Elsevier B.V. All rights reserved.