Keisar David, Garzozi Anan, Shoham Moshe, Greenblatt David
Grand Technion Energy Program (GTEP), Technion - Israel Institute of Technology, Technion Campus, Haifa 3200003, Israel.
Faculty of Mechanical Engineering, Technion - Israel Institute of Technology, Technion Campus, Haifa 3200003, Israel.
Exp Therm Fluid Sci. 2023 Feb 1;141:110777. doi: 10.1016/j.expthermflusci.2022.110777. Epub 2022 Sep 18.
Recently, a fluidic facemask concept was proposed to mitigate the transmission of virus-laden aerosol and droplet infections, such as SARS-CoV-2 (COVID-19). This paper describes an experimental investigation of the first practical fluidic facemask prototype, or "Air-Screen". It employs a small, high-aspect-ratio, crossflow fan mounted on the visor of a filter-covered cap to produce a rectangular air jet, or screen, in front of the wearer's face. The entire assembly weighs less than 200 g. Qualitative flow visualization experiments using a mannequin clearly illustrated the Air-Screen's ability to effectively block airborne droplets (∼10 µm) from the wearer's face. Quantitative experiments to simulate droplets produced during sneezing or a wet cough (∼10 µm) were propelled (via a transmitter) at an average velocity of 50 m/s at 1 m from the mannequin or a target. The Air-Screen blocked 62% of all droplets with a diameter of less than 150 µm. With an Air-Screen active on the transmitter, 99% of all droplets were blocked. When both mannequin and transmitter Air-Screens were active, 99.8% of all droplets were blocked. A mathematical model, based on a weakly-advected jet in a crossflow, was employed to gain greater insight into the experimental results. This investigation highlighted the remarkable blocking effect of the Air-Screen and serves as a basis for a more detailed and comprehensive experimental evaluation.
最近，有人提出了一种流体面罩概念，以减轻携带病毒的气溶胶和飞沫感染（如严重急性呼吸综合征冠状病毒2，即新冠病毒）的传播。本文描述了对首个实用流体面罩原型，即“空气屏障”的实验研究。它在一个覆盖有过滤器的帽子的帽舌上安装了一个小型、高纵横比的横流风扇，以在佩戴者面部前方产生一股矩形气流，即屏障。整个组件重量不到200克。使用人体模型进行的定性流动可视化实验清楚地表明了空气屏障有效阻挡佩戴者面部空气传播飞沫（约10微米）的能力。模拟打喷嚏或湿咳（约10微米）产生的飞沫的定量实验中，飞沫（通过发射器）以50米/秒的平均速度从距离人体模型或目标1米处发射。空气屏障阻挡了62%直径小于150微米的所有飞沫。当发射器上的空气屏障开启时，99%的所有飞沫被阻挡。当人体模型和发射器上的空气屏障都开启时，99.8%的所有飞沫被阻挡。采用了一个基于横流中弱平流射流的数学模型，以更深入地了解实验结果。这项研究突出了空气屏障显著的阻挡效果，并为更详细和全面的实验评估奠定了基础。
