Cross‐flow filtration of fine suspensions through microsieves occurs in microprocessing. The interaction of particles with surfaces in microenvironments has been extensively studied, but predominantly in monolayers and not with an eye to microfiltration. Here, we introduce a microfiltration model that pertains to particles that might be seen as fine in a macroscopic environment, but are large enough to intrude significantly into the shear layer of a microchannel. Thus, particle accumulation upon the sieve couples the steady‐state filtrate flux and the suspension flow through the microchannel that feeds the sieve. We envision and create a stable, stationary multilayer of particles whose thickness is shear‐limited and we identify and verify the structure and parameters that limit steady filtration in this environment. At first, a packed bed of particles forms, growing into and regulated by the micro channel's shear flow. A critical shear stress is shown to determine the thickness of the bed, seen as a stationary and stable multilayer of particles through which filtration may occur. As the bed thickens, at the expense of channel area for suspension flow, surface shear stress increases until no further particle adherence is possible. We built a simple example using hard noninteracting polymer microspheres and conducted cross‐flow filtration experiments over Aquamarijn™ microsieves (uniform pore size of 0.8 μm). We observed a steady cake‐layer thickness and because of the simple geometry afforded by uniform spheres, we could approximate the force balance, cake resistance, and filtration rate from first principles. The good fit of our data to the proposed mechanism lays a firm basis for the semiquantitative analysis of the behavior of more complex suspensions. © 2018 American Institute of Chemical Engineers AIChE J, 65: 207–213, 2019

中文翻译：

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悬浮液错流微滤中的结垢建模

在微处理过程中，会通过微筛对细悬浮液进行错流过滤。在微环境中，颗粒与表面的相互作用已经得到了广泛的研究，但是主要是在单层中，而不是着眼于微滤。在这里，我们介绍了一种微滤模型，该模型涉及在宏观环境中可能被视为精细但足够大以显着侵入微通道剪切层的颗粒。因此，颗粒在筛子上的积聚耦合了稳态滤液通量和悬浮液，流经向筛子供料的微通道。我们设想并创建了一个稳定的，固定的，多层的颗粒，其厚度受到剪切的限制，我们确定并验证了在这种环境下限制稳定过滤的结构和参数。首先，形成堆积的颗粒床，生长到微通道的剪切流中并受其调节。显示了临界剪切应力来确定床的厚度，该厚度被视为可通过其发生过滤的固定且稳定的颗粒多层。随着床层变厚，以悬浮液流动的通道面积为代价，表面剪切应力增加，直到无法进一步附着颗粒为止。我们使用坚硬的非相互作用聚合物微球构建了一个简单的示例，并在Aquamarijn™微筛（孔径统一为0.8μm）上进行了错流过滤实验。我们观察到稳定的滤饼层厚度，并且由于均匀球体提供的简单几何形状，我们可以从第一个原理近似估算力平衡，滤饼阻力和过滤速率。我们的数据与拟议机制的良好拟合为更复杂的悬架行为的半定量分析奠定了坚实的基础。©2018美国化学工程师学会AIChE J，65：207–213，2019