Zhao Yu, Feng Yao, Ma Liangdong
School of Civil Engineering, Faculty of Infrastructure Engineering, Dalian University of Technology, 2 Linggong Road, Ganjingzi District, Dalian, 116024, China.
Build Environ. 2022 Oct;224:109527. doi: 10.1016/j.buildenv.2022.109527. Epub 2022 Aug 31.
The dispersion of the coronavirus pandemic has caused immense damage worldwide, and people have begun to ruminate epidemic prevention strategies for public places. Airport terminals with a high number of occupied passengers have become potentially high-risk regions for aerosol transmission of coronavirus disease 2019 (COVID-19). In this study, the Eulerian-Lagrangian approach and realizable turbulence model were used to numerically simulate airflow organization and aerosol transmission when passengers are moving slowly in a line. During the aerosol transmission period, evaporation was considered a key factor influencing the particle size distribution at the beginning of aerosol transmission from humans. Moreover, passenger movement at the airport terminal was attained by employing dynamic mesh algorithms. Based on the relative direction of passengers and air vents when queuing in the terminal building, we studied three conditions: windward walking, leeward walking, and crosswind walking. The results of this study showed that the walking has an important influence on droplet distribution. Droplet distribution indicates that individuals standing behind patients during queuing movements have a higher risk of infection than those standing in front of them. A significant aerosol accumulation was discovered at 0.5 m behind the patient when passengers moved simultaneously. An aerosol transmission distance of 15 s aligned with the passenger's walking direction could reach up to 9.32 m. Furthermore, although the evaporation time of the large droplets was longer than that of the small droplets, both large and small droplets evaporated rapidly after exhalation. The crosswind influence caused the droplets to travel farther away in a direction perpendicular to human movement, which increased the distance by approximately 1.26 m compared to the absence of the crosswind influence.
新型冠状病毒大流行的扩散在全球范围内造成了巨大破坏，人们开始思考公共场所的防疫策略。乘客密集的机场航站楼已成为2019冠状病毒病（COVID-19）气溶胶传播的潜在高风险区域。在本研究中，采用欧拉-拉格朗日方法和可实现的湍流模型，对乘客排队缓慢移动时的气流组织和气溶胶传播进行了数值模拟。在气溶胶传播期间，蒸发被认为是影响人体气溶胶传播初期粒径分布的关键因素。此外，通过采用动态网格算法实现了机场航站楼内乘客的移动。根据航站楼内乘客排队时与通风口的相对方向，研究了三种情况：迎风行走、背风行走和侧风行走。研究结果表明，行走对飞沫分布有重要影响。飞沫分布表明，在排队移动过程中站在患者身后的个体比站在患者身前的个体感染风险更高。当乘客同时移动时，在患者后方0.5米处发现了明显的气溶胶积聚。与乘客行走方向一致的15秒气溶胶传播距离可达9.32米。此外，尽管大飞沫的蒸发时间比小飞沫长，但大小飞沫在呼出后都迅速蒸发。侧风影响使飞沫在垂直于人体运动的方向上传播得更远，与无侧风影响相比，距离增加了约1.26米。
