Analysis of fluid-dynamical and physico-chemical aspects of capillary membrane backwashing

毛细管膜反冲洗的流体动力学和物理化学方面的分析

• 批准号: 179936688
• 负责人: Professor Dr.-Ing. Rolf Gimbel
• 金额: --
• 依托单位: Lehrstuhl für Mechanik und Robotik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2010
• 资助国家: 德国
• 起止时间: 2009-12-31 至 2014-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/179936688?language=en
• 关键词: Analysis; fluid; dynamical; physico; chemical

The application of membrane filtration with Inside-Out Dead-End driven UF-/ MF- capillary membranes increases in water treatment exponentially. Thereby the required backwash process, which still is a widely unexplored field, has a high potential to enhance the efficiency of the filtration process. In order to optimize the backwash process, which should also minimize irreversible membrane fouling, an improved fundamental comprehension of the mechanisms, which are relevant for the detachment and transport-out of particles and fouling layers from Inside-Out Dead-End driven capillary membranes, is necessary. For a systematic elucidation of these mechanisms as well filtration (target-oriented build-up of fouling layers) and backwash experiments will be performed under defined operation conditions with especially designed laboratory plants. The obtained results (which parts from the fouling layer will detach under what conditions and from which zone of the capillary membrane) will be used as process parameters for a CFD supported numerical simulation of multiphase flow in capillary membranes. The multiphase flow modelling bases on the Euler-Euler method considering the most important forces acting on moving non-Brownian particles. Additionally, hydrodynamic wall effects, particle interactions (collisions and agglomeration) as well was porosity of particle collectives will be regarded. A free open source OpenFOAM and the commercial software CFX 12 will be applied in order to compare both frameworks from the numerical point of view and contribute to the validation of the results. The attained knowledge of backwash mechanisms will be applied to develop optimized backwash conditions with regard to different geometries of the capillary. The optimized backwash modes will be verified using an automated commercial membrane system for long-term experiments.

内外式死端驱动膜过滤在水处理中的应用呈指数级增长。因此，所需的反冲洗过程仍是一个广泛探索的领域，具有提高过滤过程效率的高潜力。为了优化反冲洗过程，使不可逆膜污染最小化，有必要更好地理解与内向外死端驱动毛细管膜的颗粒和污染层的分离和向外传输相关的机理。为了系统地阐明这些机理以及过滤(目标导向的污垢层积聚)和反冲洗实验，将在特定的操作条件下与特别设计的实验室设备进行。所得结果将作为CFD支持的毛细管膜内多相流数值模拟的工艺参数。多相流模型基于Euler-Euler方法，考虑了作用在运动的非布朗颗粒上的最重要的力。此外，还将考虑流体动力壁面效应、颗粒相互作用(碰撞和团聚)以及颗粒集体的孔隙率。将使用免费开放源码OpenFOAM和商业软件CFX 12，以便从数值角度对两个框架进行比较，并有助于验证结果。所获得的反冲洗机理知识将被应用于开发针对不同毛细管几何形状的最佳反冲洗条件。优化的反冲洗模式将使用自动商业膜系统进行长期实验验证。