Lai Alvin C K, Cheng Y C
Department of Building and Construction, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong.
Carrier Transicold Pte Ltd, 251, Jalan Ahmad Ibrahim, Singapore 629146, Singapore.
Atmos Environ (1994). 2007 Nov;41(35):7473-7484. doi: 10.1016/j.atmosenv.2007.05.045. Epub 2007 Jun 2.
Understanding of droplet nuclei dispersion and transport characteristics can provide more engineering strategies to control transmission of airborne diseases. Droplet dispersion in a room under the conventional well-mixed and displacement ventilation is simulated. Two droplet nuclei sizes, 0.01 and 10 μm, are selected as they represent very fine and coarse droplets. The flow field is modeled using RNG model. A new Eulerian drift-flux methodology is employed to model droplet phase. Under the conventional ventilation scheme, both fine and coarse droplets are homogeneously dispersed within approximately 50 s. Droplet nuclei exhibit distinctive dispersion behavior, particularly for low airflow microenvironment. After 270 s of droplet emission, gravitational settling influences the dispersion for 10 μm droplets, and concentration gradient can still be observed for displacement ventilation.
了解飞沫核的扩散和传输特性可为控制空气传播疾病的传播提供更多工程策略。模拟了传统的全混合通风和置换通风条件下室内的飞沫扩散情况。选择了0.01微米和10微米这两种飞沫核尺寸，因为它们分别代表极细和较粗的飞沫。采用RNG模型对流场进行建模。采用一种新的欧拉漂移通量方法对液滴相进行建模。在传统通风方案下，细飞沫和粗飞沫在大约50秒内均匀扩散。飞沫核表现出独特的扩散行为，特别是在低气流微环境中。飞沫排放270秒后，重力沉降对10微米飞沫的扩散产生影响，对于置换通风仍可观察到浓度梯度。
