大巴车飞沫扩散特性及乘客感染风险预测

Dispersion characteristics of droplet in bus and risk prediction of infection

为了研究飞沫在大巴车中的扩散特性并揭示病毒的传播规律,以空调开启状态下的大巴车为研究对象,通过对车内流场结构的分析,应用拉格朗日方法对位于车内前部、中部、后部的患者咳嗽产生飞沫的扩散过程进行计算,获取飞沫的传播路径、浓度分布、逃逸速率等扩散特性参数.根据飞沫中病毒颗粒数量,结合Wells-Riley方程对车内乘客的感染概率进行预测.研究结果表明,飞沫在舱内的分布特性与患者位置、回风口位置、气流组织等因素密切相关;与位于后部患者相比,前部患者会使更多的乘客面临较高的感染风险;位于飞沫扩散路径且距离患者三排以内的乘客感染概率均高于30%.

The bus with air-condition was chosen as research object in order to analyze the dispersion of droplet in bus and reveal the mechanism of virus transmission. The dispersion characteristic parameters of droplet such as dispersion path, concentration distribution and escape rate were obtained by the analysis of flow field. The calculation of transport of the droplets exhaled from a single cough by patient in the front, middle and back of the cabin with the Lagrangian method. Then the infection risk for passenger can be evaluated by the Wells-Riley equation according to the amount of inhaled virus particles by passenger. Results show that location of the patient and air return opening, the airflow pattern can significantly affect the droplet distribution. The patient in the front may cause more passengers at a higher infection risk compared with the patient in the back. The infection probability of passengers located in the droplet dispersion pathway and within three rows of the patient is higher than 30%.