Abstract Although membrane distillation (MD) has the potential for use in both desalination and industrial wastewater treatment, its widespread application has been hindered by its inherent limitations such as membrane fouling due to scale formation. One of the approaches to overcome this challenge is to develop novel membrane modules to mitigate the scale formation. Accordingly, this study sought to devise a way to control scale formation in MD systems using baffles in the modules. Moreover, the analysis based on computational fluid dynamics (CFD) was carried out together with bench-scale experiments to understand the hydrodynamic conditions in MD modules. CFD model was developed and applied to analyze flow velocity, shear stress, and vorticity. CFD analysis revealed that the baffled-modules can provide higher shear stress and generate both oscillatory mixing and vortices. Experimental results showed that fouling due to scale formation was more efficiently mitigated in the modules with the orifice baffles than the other modules. The final flux was increased from 2 L/m2-hr in the basic module to up to 19 L/m2-hr in the module with three orifice holes. According to the CFD results, it is attributed to the retardation of crystal deposition and cake formations by increased shear stress and vortices.

中文翻译：

---

在直接接触膜蒸馏 (DCMD) 中使用挡板系统减轻无机污染

摘要 尽管膜蒸馏 (MD) 具有用于海水淡化和工业废水处理的潜力，但由于其固有的局限性，例如由于结垢导致膜污染，阻碍了其广泛应用。克服这一挑战的方法之一是开发新型膜组件以减轻水垢的形成。因此，本研究试图设计一种方法来控制使用模块中的挡板的 MD 系统中的水垢形成。此外，基于计算流体动力学 (CFD) 的分析与实验室规模的实验一起进行，以了解 MD 模块中的流体动力学条件。开发并应用 CFD 模型来分析流速、剪切应力和涡度。CFD 分析表明，挡板模块可以提供更高的剪切应力并产生振荡混合和涡流。实验结果表明，带有孔板挡板的模块比其他模块更有效地减轻了由于水垢形成造成的污垢。最终通量从基本模块中的 2 L/m2-hr 增加到具有三个孔口的模块中的 19 L/m2-hr。根据 CFD 结果，这归因于增加的剪切应力和涡流导致晶体沉积和饼形成的延迟。最终通量从基本模块中的 2 L/m2-hr 增加到具有三个孔口的模块中的 19 L/m2-hr。根据 CFD 结果，这归因于增加的剪切应力和涡流导致晶体沉积和饼形成的延迟。最终通量从基本模块中的 2 L/m2-hr 增加到具有三个孔口的模块中的 19 L/m2-hr。根据 CFD 结果，这归因于增加的剪切应力和涡流导致晶体沉积和饼形成的延迟。