Simulation study on the effect of air supply and exhaust terminals to coughed droplet diffusion in NPI ward

Abstract

The numerical (CFD) method is applied in this paper to investigate the nonuniformity of temperature and airflow filed, the spatial and temporal distribution of coughed droplet under stratum ventilation and mixing ventilation in the negative pressure isolation (NPI) ward. The influence of exhaust terminals number and location on the diffusion process of coughed droplet is analyzed under heating mode. The results show that the relative pollutant concentration in the breathing area of stratum ventilation is lower than that of mixing ventilation. When the air exhaust terminals are high from the ground and the number are small, it is more conducive to reduce the infection risk of medical staff. The deposition rate and suspension rate of stratum ventilation are higher than that of mixing ventilation, and the escape rate is lower. When the number of exhaust outlets is large and the location is high, the nonuniformity coefficient is the smallest and the deposition rate is the largest, which are 0.668, 0.029 and 91.4% respectively. The escape rate is higher when the number of exhaust outlets is small and the location is high, and the suspension rate is higher when the number of exhaust outlets is large and the location is low, which are 27.9% and 1.11% respectively.