室内密闭与通风空间气溶胶扩散特性

由于气溶胶具有传播病毒的特性，室内密闭与通风空间的气溶胶扩散特性具有重要的研究意义。针对密闭空间、人体模型进行等比例建模、数值仿真计算，获取气溶胶颗粒瞬态传播途径与范围。并采用Realizable k-ε湍流模型、DPM（离散项模型）开展两相瞬态计算。结果表明:打喷嚏、咳嗽等呼出条件下，大直径颗粒降沉，小直径颗粒将随气流传播到2 m外人体头部区域。由于人体体温高于室内环境温度，在体表附近将出现热羽流现象，气溶胶颗粒将随其向上流动，并在顶部随环流向下运动。通过稳态通风方案仿真研究，发现在前侧、左侧、右侧（相对与门）3种通风方案中，左侧与右侧通风均在人体模型下方出现2个回流涡，占据中央区域的涡流将造成颗粒在此停留。前侧通风方案中64.8%的颗粒随气流流出，左侧方案占59.3%次之，而右侧通风的颗粒流出效果较差，占46.9%。因此，3种方案中，前侧通风方案效果最佳。可为有人员在室内时，室内空间通风方式的选取，以及减少室内呼吸气溶胶颗粒物提供参考。

AEROSOL DIFFUSION CHARACTERISTICS IN CLOSED AND VENTILATED SPACES

Since aerosols have the characteristics of spreading viruses, the aerosol diffusion characteristics of indoor closed and ventilated spaces have important research significance. The proportional modeling of closed spaces and human body models were established, and numerical simulation calculations were carried to obtain the transient propagation path and range of aerosol particles. In this paper, Realizable k-ε turbulence model and DPM (discrete phase model) were used to carry out two-phase transient calculations. The results showed that under exhalation conditions such as sneezing and coughing, large-diameter particles would sink, and small-diameter particles would spread to the human head area at 2 m away with the airflow. Due to the temperature of the human body was higher than the temperature of the surrounding environment, the thermal plume would appear near the body, and the aerosol particles would flow upward with it and move downward with the circulation at the top. Through the simulation study of steady ventilation schemes, it was found that in the three ventilation schemes on the front side, left side, and right side (relative to door), two vortices appeared under the body model for both left and right ventilation. The vortex occupying the central area would cause the particles to stay here. In the front ventilation scheme, 64.8% of the particles flowed out with the air flow, followed by the left scheme, 59.3%, and the right ventilation scheme had a poorer outflow effect, accounting for 46.9%. Therefore, among the three schemes, the front side ventilation scheme had a better effect. It could provide reference for the selection of indoor ventilation mode and the reduction of indoor breathing aerosol particles when people were indoors.