通风模式对住舱人员咳嗽液珠扩散过程的影响

针对邮轮上呼吸道疾病发病率高及缺乏相关定量研究的现状,采用计算流体力学方法分析了游客在密闭住舱内因为咳嗽产生的液珠在空气中的传播扩散过程,对空气流动采用非定常雷诺平均纳维-斯托克斯方程求解,对液珠扩散采用欧拉模型求解,计算工况考察了改变通风模式和加大通风量等方式降低液珠浓度的控制效果。研究结果表明:加大通风量在置换通风模式比混合通风模式下可更好地控制液珠的扩散,混合通风模式需要3次换气才能把住舱内的液珠基本排空,而置换通风模式仅需2次换气,且住舱内液珠平均浓度的下降服从指数分布。此外,游客睡姿对呼吸区域内液珠浓度峰值和吸入剂量有较大影响。

Influences of ventilation modes on the coughing droplet dispersion process in a cruise cabin

Aiming at problem of the high infection rate of respiratory diseases on cruise ships and the corresponding lack of quantitatively research, the Computational Fluid Dynamics(CFD) method is adopted in this paper to analyze the droplet transmission and dispersion process coughed by an infected passenger accommodated in an enclosed cabin quantitatively.The air flow equation is solved by solving the unsteady Reynolds averaged Navier-Stokes equations while the Eulerian model is used to simulate the coughed droplet dispersion.The controlling effects for reducing the droplet concentration are also investigated under various conditions of changing ventilation modes and increasing ventilation rates.The results show that the displacement ventilation mode is superior to the mixed ventilation mode when increasing the ventilation rate to control the droplet dispersion.The mixed ventilation mode needs at least three air changes to empty the droplet, while the displacement ventilation mode needs only two, and the reduction of averaged droplet concentration obeys exponential distribution.In addition, the sleeping gestures of the infector have big influences on the droplet concentration in the breathing zone and inhaled dose of the susceptible.