公交车内飞沫运移的数值模拟

基于计算流体力学数值模拟方法，研究了送风风速0.25~2m/s及乘客位于车厢前、中、后部时咳嗽产生飞沫的蒸发、沉降和扩散运动.结果表明:飞沫喷出后迅速蒸发;当车厢进风速度小时，大粒径飞沫迅速沉降，小粒径飞沫在空间停留时间长，影响范围大;当进风速度大时，大粒径飞沫在空间停留时间变长，传播更远，小飞沫停留时间变短;综合考虑，本模型条件下推荐车厢进风速度为1m/s.患者位于车厢前部时，飞沫主要沉降在车壁，其次为地面;患者位于车中部和后部时，飞沫主要沉降在人及座位上，其次为地面;相较于前部和中部，患者在车厢后部咳嗽时飞沫影响范围大.本研究可为公交车内通风和消杀提供指导.

Numerical Simulation of Droplet Transport in Bus

Based on the numerical simulation method of computational fluid dynamics， the evaporation， sedimentation and diffusion of droplets produced by coughing when the air velocity is 0.25~2m/s and the passengers are in the front， middle and rear of the car compartment are studied. The results show that the droplets evaporate quickly after spraying. When the air inlet velocity is small， the large-particle droplets will settle rapidly， and the small-particle droplets will stay in the space for a long time and have a large influence. When the air inlet velocity is high， the large droplets stay in the space longer and spread farther， while the small droplets stay in the space for a short time. Considering comprehensively， the recommended air inlet speed of the carriage is 1m/s under the conditions of this model. When the patient is in the front of the vehicle， the droplets mainly settle on the vehicle wall， followed by the ground. When the patient is in the middle and rear of the car， the droplets mainly settle on people and seats， followed by the ground. Compared with the front and the middle， the droplets have a larger impact when the patient coughs in the back of the compartment. This study can provide guidance for the correct understanding of droplet propagation， ventilation and elimination in bus.