Despite their ubiquitous use in large-scale filtration processes, the benefits of adding spacers on the microscale—if any—remain unknown. At larger scales, spacers improve performance by directing the flow and inducing turbulent mixing. However, at low Reynolds numbers, it becomes increasingly difficult to initiate mixing because viscous forces dominate over inertial forces. In membrane filtration applications, concentration polarization and membrane fouling can severely limit filtration efficiency, and even a small amount of fluid mixing presents potential to mitigate these issues. In this study, three complex 3D-printed microspacer designs (with feature sizes in the range of 100–400 µm) were incorporated into narrow channels to consider their enhancement effects for microfiltration and ultrafiltration applications. These structures included two herringbone designs and one triply periodic minimal surface, e.g. a ‘gyroid’ spacer. Experiments and simulations found that the gyroid design achieved the highest membrane flux enhancement (i.e. 81 and 93% above a plain channel for blood mimicking and plasma mimicking solution tests, respectively). This was significantly better than the enhancement by herringbone designs. All of the spacers added back-pressure, with gyroid incurring a 23% higher pressure drop than the plain channel, which was considered as an acceptable performance trade-off. Based upon this work, 3D-printed microspacers were shown to enhance mixing and improve membrane filtration by reducing concentration polarization and fouling. Further, this study indicates that 3D printing can enable a promising new class of efficient, small-format devices for filtration processes.

尽管它们在大规模过滤过程中无处不在，但在微尺度上添加垫片的好处（如果有）仍然未知。在较大规模上，垫片通过引导流动并引起湍流混合来改善性能。然而，在低雷诺数下，由于粘性力超过惯性力，开始混合变得越来越困难。在膜过滤应用中，浓差极化和膜结垢会严重限制过滤效率，即使少量的流体混合也可能缓解这些问题。在这项研究中，将三种复杂的3D打印微间隔器设计（特征尺寸在100-400 µm范围内）并入狭窄的通道，以考虑它们对微滤和超滤应用的增强作用。这些结构包括两种人字形设计和一个三重周期性的最小表面，例如“回旋”垫片。实验和模拟发现，该陀螺仪设计实现了最高的膜通量增强（即，对于血液模拟和血浆模拟溶液测试，分别比普通通道高81％和93％）。这明显优于人字形设计的增强。所有的垫片都增加了背压，与普通通道相比，螺旋管的压降高出23％，这被认为是可以接受的性能折衷。基于这项工作，显示了3D打印的微间隔物可通过减少浓度极化和结垢来增强混合并改善膜过滤。此外，这项研究表明3D打印可以为过滤过程提供一种有希望的新型高效，小尺寸设备。分别比普通通道高81％和93％，用于血液模拟和血浆模拟溶液测试。这明显优于人字形设计的增强。所有的垫片都增加了背压，与普通通道相比，螺旋管的压降高出23％，这被认为是可以接受的性能折衷。基于这项工作，显示了3D打印的微间隔物可通过减少浓度极化和结垢来增强混合并改善膜过滤。此外，这项研究表明3D打印可以为过滤过程提供一种有希望的新型高效，小尺寸设备。分别比普通通道高81％和93％，用于血液模拟和血浆模拟溶液测试。这明显优于人字形设计的增强。所有的垫片都增加了背压，与普通通道相比，螺旋管的压降高出23％，这被认为是可以接受的性能折衷。基于这项工作，显示了3D打印的微间隔物可通过减少浓度极化和结垢来增强混合并改善膜过滤。此外，这项研究表明3D打印可以为过滤过程提供一种有希望的新型高效，小尺寸设备。螺旋桨的压力降比平通道高23％，这被认为是可以接受的性能折衷。基于这项工作，显示了3D打印的微间隔物可通过减少浓度极化和结垢来增强混合并改善膜过滤。此外，这项研究表明3D打印可以为过滤过程提供一种有希望的新型高效，小尺寸设备。螺旋桨的压力降比平通道高23％，这被认为是可以接受的性能折衷。基于这项工作，显示了3D打印的微间隔物可通过减少浓度极化和结垢来增强混合并改善膜过滤。此外，这项研究表明3D打印可以为过滤过程提供一种有希望的新型高效，小尺寸设备。