Akagi Fujio, Haraga Isao, Inage Shin-Ichi, Akiyoshi Kozaburo
Faculty of Engineering, Fukuoka University, 8-19-1 Nanakuma, Jyounan-ku, Fukuoka, Japan.
Department of Anesthesiology, Faculty of Medicine, Fukuoka University, 7-45-1 Nanakuma, Jyounan-ku, Fukuoka, Japan.
Phys Fluids (1994). 2021 Mar;33(3):037131. doi: 10.1063/5.0044367. Epub 2021 Mar 26.
A flow simulation was performed for face shields to investigate whether varying a shield's edge shape could prevent droplets from entering the shield. Face shields with two types of edge shapes were used. The "Type I" shield had small plates mounted on the top and bottom edges of the shield to physically inhibit the sneeze inflow. The "Type II" shield had small brims sticking forward from the shield surface and small plates sticking upward and downward at the top and bottom edges to inhibit the entrainment flow produced by the vortex ring using sneeze flow. We confirmed that the flow characteristics around a face shield can be controlled using the shield's edge shape. In Type I, the entraining flow inside the shield was inhibited by the mounted small plate at the bottom edge, ensuring the inhibiting effect, but not at the top edge. In Type II, the entrained flow inside the shield was inhibited by the mounted brim and small plate at the top edge, ensuring the inhibiting effect, but not at the bottom edge. The effects of the Type II design parameters on the flow characteristics around the face shield were examined. The results indicate that at the top edge, increasing the length of the brim and not mounting the small plate at an incline from the shield surface improves the inhibition effect. At the bottom edge, shortening the length of the brim and mounting the small plate at an incline from the shield surface improves the inhibition effect.
对面罩进行了流动模拟，以研究改变面罩边缘形状是否能防止飞沫进入面罩。使用了两种边缘形状的面罩。“I型”面罩在面罩的顶部和底部边缘安装了小板，以物理方式抑制喷嚏气流的流入。“II型”面罩有从面罩表面向前伸出的小帽檐，以及在顶部和底部边缘向上和向下伸出的小板，以利用喷嚏气流抑制由涡环产生的夹带气流。我们证实，可以使用面罩的边缘形状来控制面罩周围的流动特性。在I型中，面罩底部边缘安装的小板抑制了面罩内部的夹带气流，确保了抑制效果，但顶部边缘没有。在II型中，面罩顶部边缘安装的帽檐和小板抑制了面罩内部的夹带气流，确保了抑制效果，但底部边缘没有。研究了II型设计参数对面罩周围流动特性的影响。结果表明，在顶部边缘，增加帽檐长度且不将小板从面罩表面倾斜安装可提高抑制效果。在底部边缘，缩短帽檐长度并将小板从面罩表面倾斜安装可提高抑制效果。
