PDF(Pubmed)
Abstract：
The three-layer surgical mask was recognized by the World Health Organization as an effective-protection tool for reducing SARS-CoV-2 transmission during the COVID-19 pandemic; however, the contribution of each layer of this mask to the particle size-dependent filtration performance resistance remains unclear. Here, both experimental work and numerical simulation were conducted to study the role of each mask layer in particle size-dependent filtration and respiratory resistance. By using scanning electron microscopy images of a commercial three-layer mask, composed of two spun-bond and one melt-blown nonwoven polypropylene fabric layers, four representative models were constructed, in which the computational fluid dynamics of multiphase flow were performed. The pressure drop of all models under different flow conditions was measured next. Numerical simulation was then verified by comparing the experimental results in the present study and other theoretical works. The filtration efficiency of the spun-bond polypropylene nonwoven fabric layer was much lower than that of the melt-blown nonwoven polypropylene fabric layer for the particle diameter in the range of 0.1-2.0 μm. Both the spun-bond and melt-blown nonwoven polypropylene fabric layers demonstrated extremely low filtration efficiency for particles was<0.3 μm in diameter, with the maximum filtration efficiency being only 30%. The present results may facilitate rational design of mask products in terms of layer number and structural design.
摘要：
三层外科口罩被世界卫生组织认可为在COVID-19大流行期间减少SARS-CoV-2传播的有效保护工具；然而，该面罩的每一层对颗粒尺寸依赖性过滤性能阻力的贡献仍不清楚。这里,进行了实验工作和数值模拟，以研究每个面罩层在粒径依赖性过滤和呼吸阻力中的作用。通过使用商用三层掩模的扫描电子显微镜图像，由两层纺粘和一层熔喷非织造聚丙烯织物组成，构建了四个代表性模型，其中进行了多相流的计算流体动力学。接下来测量所有模型在不同流动条件下的压降。然后通过将本研究中的实验结果与其他理论工作进行比较来验证数值模拟。对于0.1-2.0μm的粒径,纺粘聚丙烯无纺布层的过滤效率远低于熔喷聚丙烯无纺布层的过滤效率。对于直径<0.3μm的颗粒，纺粘和熔喷非织造聚丙烯织物层都显示出极低的过滤效率，最大过滤效率仅为30%。目前的结果可以促进掩模产品在层数和结构设计方面的合理设计。
