地铁车厢内病原体佩戴口罩对飞沫病毒传播抑制效果的模拟研究  

A Simulation Study on the Mitigation Effect of Masks on the Transmission of Virus in Droplets in Subway Compartments

作　　者：薛宇 叶蔚[1,2] 张旭[1] XUE Yu;YE Wei;ZHANG Xu(School of Mechanical Engineering,Tongji University,Shanghai 201804,China;Key Laboratory of Performance Evolution and Control for Engineering Structures of Ministry of Education,Tongji University,Shanghai 200092,China)

机构地区：[1]同济大学机械与能源工程学院,上海201804 [2]同济大学工程结构性能演化与控制教育部重点实验室,上海200092

出　　处：《建筑科学》2020年第10期114-118,共5页Building Science

基　　金：“十三五”国家重点研发计划专项资助“建筑室内空气质量控制的基础理论和关键技术研究”(2017YFC0702700)。

摘　　要：以计算流体力学(CFD)方法对地铁车厢内病原体佩戴口罩咳嗽飞沫传播病毒,同乘者感染风险进行研究。选取人员密集的地铁车厢为场景,假定车厢内存在飞沫传播病毒,对比典型地铁区间运行时间(120 s)内某病原体未佩戴口罩、佩戴棉布、无气阀KN95等型号口罩后对飞沫传播病毒的抑制效果。结果表明,佩戴口罩可抑制飞沫传播,有口罩工况下飞沫在成人呼吸高度(1.5 m)扩散距离较无口罩工况降低36%,且阻力较大,孔隙率较小的口罩飞沫抑制效果更好;佩戴口罩可以改变飞沫传播方向,低身高儿童群体(1.2 m)所接触的飞沫浓度可降低95%;地铁内与病原体距离超过两个身位的乘客接触飞沫浓度低,感染风险小,病原体邻坐,对面及排风口附近乘客接触浓度较高,感染风险大。本文计算结果可用于指导地铁车厢通风空调设计,对高浓度飞沫区域进行局部通风控制,并为地铁人员飞沫病毒防护安全距离提供依据。In this paper,the computational fluid dynamics(CFD)method was used to study the risk of infection for passengers when assuming a pathogen wears a mask and,nonetheless,spreads the virus through cough droplets in a densely-populated subway compartment.The changes of droplet virus transmission in the following scenarios,i.e.,a pathogen does not wear a mask,wears a cotton mask,or wears a valve-less KN95 mask,are compared,during a typical period(120 s)for a subway train operates between two stations.The results show that,first,wearing a mask is conducive to suppressing the spread of droplets,and the diffusion distance of droplets at adult breathing height(1.5 m)is 36%lower than that without masks.The greater resistance and smaller porosity of the masks,the fewer droplets would diffuse out of the pathogen.Second,by wearing a mask,the direction of droplet transmission can be changed,and the concentration of droplets exposed to children of lower height(e.g.,1.2 m)can be reduced by approximately 95%.Passengers who are in indirect contact with the pathogen(e.g.,more than two passengers in between)would expose to low concentrations of droplets and bear low risks of infection.Passengers who are in adjacent or opposite-side seats,or close to the exhaust vents of the compartment would expose to high concentrations of droplets and,therefore,are in high risks of infection.The results can be used to guide the ventilation and air-conditioning design of subway compartment(e.g.,local ventilation for areas with high concentrations of droplets),and provide a basis for the safety distance of subway personnel protection.

关 键 词：飞沫扩散 口罩 地铁 感染风险 计算流体力学 

分 类 号：TU831[建筑科学—供热、供燃气、通风及空调工程]