CAREER: Robust Numerical Modeling for Rational Design of Membrane Filtration Processes

城市、工业和农业对饮用水的需求不断增长，导致水资源短缺，威胁到全球能源、粮食和经济安全。膜分离工艺为海水淡化和废水处理提供了有前途的低能耗解决方案。然而，溶质保留在膜的进料侧，称为浓差极化，增加了迫使流体穿过膜表面所需的压力。 随着时间的推移，溶质的积累形成阻碍过滤、损坏膜并增加维护成本的矿物质垢。许多正在进行的研究工作正在探索物理和化学策略来防止结垢。其中一种策略是在膜上形成物理间隔物的网状网络，从而改变表面的流体流动。这种模式化产生了复杂的流体流动动力学，这是不太清楚的，特别是增加了溶质过滤的复杂性和浓差极化的影响。这个CAREER项目将开发一个经过验证的计算流体动力学模型，用于反渗透和纳滤膜系统的浓差极化和矿物结垢。该项目将开发创新的计算流体动力学模拟，充分耦合极化，缩放和混合之间的相互作用，由于饲料间隔。 模拟将解决由于近膜质量传输和由于进料间隔件的三维混合而引起的并发症。这些方法将通过实验验证，然后用于：（1）开发偏振和缩放的改进模型;（2）研究间隔物和操作条件对系统性能的作用;以及（3）探索最小化偏振和缩放的新间隔物的设计。 该项目将直接培训研究生和本科生进行研究，同时也将活动纳入本科工程设计课程。与社区中心和多元文化工程项目合作开展的外联活动将向服务不足的初中和高中学生介绍计算机编程、可持续水资源问题和STEM职业。 该项目预计将加速膜的知情设计，以延长寿命和性能。该奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

The growing demands of municipalities, industry, and agriculture for potable water have provoked a water deficit that threatens global energy, food, and economic security. Membrane separation processes offer promising low-energy solutions for desalination and wastewater treatment. However, the retention of solutes on the feed side of the membrane, known as concentration polarization, increases the pressures needed to force the fluid across the membrane surface. With time, the buildup of solutes forms a mineral scale that impedes filtration, damages the membrane, and increases maintenance costs. Many on-going research efforts are exploring both physical and chemical strategies to prevent scaling. One such strategy is to pattern a mesh-like net of physical spacers on the membrane that alters the fluid flow at the surface. This patterning creates complex fluid flow dynamics that are not well understood, particularly with the added complexity of solute filtration and the effect of concentration polarization. This CAREER project will develop a validated computational fluid dynamics model of concentration polarization and mineral scaling with patterned spacers for reverse osmosis and nanofiltration membranes systems. This project will develop innovative computational fluid dynamics simulations that fully couple interactions between polarization, scaling, and mixing due to feed spacers. The simulations will address complications that arise due to both near-membrane mass transport and three-dimensional mixing due to the feed-spacers. The methods will be experimentally validated, and then used to: (1) develop improved models of polarization and scaling; (2) investigate the roles of spacers and operating conditions on system performance; and (3) explore the design of new spacers that minimize polarization and scaling. The project will directly train both graduate and undergraduates in conducting research, while also integrating the activities into undergraduate engineering design coursework. Outreach activities, in collaboration with a community center and Multicultural Engineering Program, will introduce both under-served middle and high-school students to computer programming, sustainable water issues, and STEM careers. The project is anticipated to accelerate informed design of membranes for extended lifetime and performance.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.