Numerical study of airflow pattern and bioaerosol dispersion during door motion in a negative pressure isolation ward

Abstract

Negative pressure isolation wards are typically equipped with buffer rooms to prevent the spread of infectious bioaerosols into clean areas and facilitate timely removal. The opening and closing process of sliding doors is very common in wards. Since the air exchange characteristics of the doorway affect the risk of infection and the efficiency of particle removal within the buffer room, the boundary transformation method and dynamic numerical simulations are used to study the airflow patterns and particle diffusion during door motion. The corresponding cases for different pressure differences, temperature differences, and door motion modes are compared. The results indicate that under different temperature differences, the particles can be dispersed uniformly in a short time (about 23s), and there is no phenomenon of particle aggregation. Compared to the initial pressure difference, adjusting the initial temperature difference has a more pronounced effect on air infiltration and particle concentration trends. The peak particle concentrations within the buffer zone under negative temperature differences are on average 19.9 % higher compared to the positive temperature differences. However, particle concentrations at negative initial temperature differences decay more rapidly. It is found that by reducing the duration of full door opening from 6s to 2s, the time for particles to be completely removed can be reduced by 30.6 %. This study provides useful information for evaluating the risk of infection and developing operational modes of the buffer room.