膜科学与技术

基于CFD和RSM的全效膜元件进水流道优化研究

作者：林炜琛¹，邵瑞朋¹，王乔¹，雷晶²，王小??¹，黄霞¹

单位： 1. 清华大学环境学院环境模拟与污染控制国家重点实验室，北京 100084

关键词：反渗透；卷式膜元件；进水流道；计算流体力学；响应曲面法

出版年,卷(期):页码： 2020,40(6):88-95

摘要：

新型的全效膜元件进水流道通过设置隔水带，改变了传统流道的进水方式，提高了流道的水力学性能。本研究采用计算流体力学（CFD）与响应曲面法（RSM）相耦合的方法，对比了全效膜流道与传统进水流道在水力学性能上的差异，探究了进水流道几何参数和进口流量对水力学性能的影响，并基于多目标遗传算法模型实现了优化。结果表明，CFD模拟能够很好地模拟和预测流道内的水力学行为。在操作条件相同的情况下，全效膜流道虽然相比传统进水流道的进出口压降差提高了32%，流场均匀性下降了37%，但平均流速提高了79%，壁面剪切力提高了93%，有效减小了浓差极化效应和膜污染速率。流道进口开度的增加能有效增强流场的均匀性并降低进出口压降差，但也会引起流道内平均流速和回收率的下降。优化结果表明，增加流道进口开度的同时适当提高进口流速可以有效提高全效膜流道的水力学性能。在实际的应用中，可以根据优化目标计算、选取合适的优化方案。

The feed channel of the new full-effective membrane element is equipped with a water barrier, which changes the streamlines and improves the hydraulic performance. In this study, the coupling of computational fluid dynamics (CFD) and response surface methodology (RSM) was used to compare the hydraulic performances of the full-effective membrane channel and the traditional membrane channel, explore the influence of geometric channel parameters and inlet flow rates on the hydraulic performance, and optimize the design of the full-effective membrane channel based on a multi-objective genetic algorithm model. The results show that CFD simulation can well explain and predict the hydraulic behavior in the flow channel. Under the same operating conditions, although the feed channel pressure drop and the uniformity of flow field of the full-effective membrane increased by 32% and decreased by 37%, respectively, the average cross-flow velocity increased by 79% and the shear stress increased by 93% compared to the traditional membrane channel, which can effectively reduce concentration polarization effect and membrane fouling rate. The increase of the inlet opening of the flow channel can enhance the uniformity of the flow field and reduce the feed channel pressure drop, but it will also cause the decrease of the average cross-flow velocity and the recovery rate. The optimization results show that increasing the inlet opening meanwhile appropriately increasing the inlet flow rate can effectively improve the hydraulic performance of the full-effective membrane channel. The optimization scheme should be formulated according to the actual demand.

林炜琛（1994-），男，福建省泉州市人，博士生，研究方向为膜分离技术与污水资源化，E-mail：lwc17@mails.tsinghua.edu.cn

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