Numerical simulation of aerosol permeation through microstructure of face masks coordinating with x-ray computed tomography images
Numerical simulation of aerosol permeation through microstructure of face masks coordinating with x-ray computed tomography images
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DOI：
10.1063/5.0129087
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发表时间：
2022-12
期刊：
影响因子：
1.6
通讯作者：
Kodai Hada;M. Shirzadi;Tomonori Fukasawa;K. Fukui;T. Ishigami
中科院分区：
文献类型：
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作者：
Kodai Hada;M. Shirzadi;Tomonori Fukasawa;K. Fukui;T. Ishigami
口罩作为空气过滤器，收集飞沫和气溶胶，它们被广泛用于预防传染病，如COVID-19。在这里，我们提出了一个数值模拟模型，了解收集行为的气溶胶含有亚微米尺寸的液滴内的一个现实的微观结构的市售口罩。利用X射线CT三维图像分析技术获得了两种市售口罩的微结构，并结合计算流体力学和离散相模型对微结构中气溶胶的渗透行为进行了数值模拟。为了描述实际纤维的复杂几何形状，使用壁边界模型，其中浸没边界方法用于流体相，并且使用带符号的距离函数来确定液滴和纤维表面之间的接触。制备了六种不同的面罩区域，并计算了两种不同液滴直径下的压降和液滴收集效率。具有相对较大孔隙的面罩微观结构，穿透主流方向，显示出高品质因数。一些液滴伴随着流体流动接近孔，并且纤维将它们收集在孔附近。为了验证孔对收集行为的影响，创建了六个不同的模型可变孔径的面罩域。此外，在模型面罩域中观察到孔附近的液滴收集。特定孔径的模型面具比没有的面具表现得更好，这表明大孔径可以提高性能。
Face masks act as air filters that collect droplets and aerosols, and they are widely used to prevent infectious diseases, such as COVID-19. Herein, we present a numerical simulation model to understand the collection behavior of aerosols containing submicron-sized droplets inside a realistic microstructure of commercially available face masks. Three-dimensional image analysis by x-ray computed tomography is used to obtain the microstructures of two types of commercial face masks, and the aerosol permeation behavior in the obtained microstructures is investigated with a numerical method coupled with computational fluid dynamics and a discrete phase model. To describe the complex geometry of the actual fibers, a wall boundary model is used, in which the immersed boundary method is used for the fluid phase, and the signed distance function is used to determine the contact between the droplet and fiber surface. Six different face-mask domains are prepared, and the pressure drop and droplet collection efficiency are calculated for two different droplet diameters. The face-mask microstructure with the relatively larger pore, penetrating the main flow direction, shows a high quality factor. A few droplets approach the pore accompanied by fluid flow and fibers collect them near the pore. To verify the effect of the pore on the collection behavior, six different model face-mask domains of variable pore sizes were created. Additionally, droplet collection near the pore is observed in the model face-mask domains. Specific pore-sized model masks performed better than those without, suggesting that the large pore may enhance performance.