Modelling of evaporation of cough droplets in inhomogeneous humidity fields using the multi-component Eulerian-Lagrangian approach
Modelling of evaporation of cough droplets in inhomogeneous humidity fields using the multi-component Eulerian-Lagrangian approach
复制标题
使用多分量欧拉-拉格朗日方法对不均匀湿度场中咳嗽飞沫的蒸发进行建模
DOI：
10.1016/j.buildenv.2017.11.025
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发表时间：
2018-01-15
影响因子：
7.4
通讯作者：
Tu, Jiyuan
中科院分区：
文献类型：
--
作者：
Li, Xiangdong;Shang, Yidan;Tu, Jiyuan
本研究采用多分量欧拉-拉格朗日方法模拟咳嗽液滴在静止空气中的蒸发和扩散。该方法通过显式求解连续性方程，可以综合考虑非均匀湿度场对液滴蒸发和运动的影响。计算流体动力学（CFD）计算的基础上的方法取得了令人满意的协议与文献中报道的理论模型。结果表明，蒸发产生的蒸汽和从呼吸道呼出的过饱和湿空气在呼吸道开口前形成“蒸汽羽流”，尽管其寿命较短，但显著阻碍了其中捕获的液滴的蒸发。研究还表明，由于蒸发引起的液滴尺寸减小，空气飞沫的数量密度和可吸入病原体的质量浓度均显著增加，这可导致更高的感染风险。最后进行参数研究，以评估影响液滴evaporation.Summary的因素：该研究表明，考虑不均匀的湿度场建模时的咳嗽液滴的蒸发和分散的重要性。本研究中提出的多组分欧拉-拉格朗日模型提供了一种综合方法，可以在较宽的参数范围内解决不同的影响因素，这将有助于评估与液滴暴露相关的健康风险。
This study employed a multi-component Eulerian-Lagrangian approach to model the evaporation and dispersion of cough droplets in quiescent air. The approach is featured with a continuity equation being explicitly solved for water vapor, which allows comprehensively considering the effects of inhomogeneous humidity field on droplets evaporation and movement. The computational fluid dynamics (CFD) computations based on the approach achieved a satisfactory agreement with the theoretical models reported in the literature. The results demonstrated that the evaporation-generated vapor and super-saturated wet air exhaled from the respiratory tracks forms a "vapor plume" in front of the respiratory track opening, which, despite the short life time, significantly impedes the evaporation of the droplets captured in it. The study also revealed that due to the droplet size reduction induced by evaporation, both the number density of airborne droplets and mass concentration of inhalable pathogens remarkably increased, which can result in a higher risk of infection. Parametric studies were finally conducted to evaluate the factors affecting droplet evaporation.Summary: The study demonstrated the importance of considering inhomogeneous humidity field when modelling the evaporation and dispersion of cough droplets. The multi-component Eulerian-Lagrangian model presented in this study provides a comprehensive approach to address different influential factors in a wide parametric range, which will enhance the assessment of the health risks associated with droplet exposure.