Effect of the room air motion on the dispersion of expiratory droplets in the Personalized Ventilated room

Abstract

A discrete phase numerical model was adopted for the expiratory droplet simulation. Expiratory droplets were simulated as an unsteady source at the distance of 2 m sideways from the manikin nose at the height of 1.7 m. Cough droplets were represented with 4 different droplet size bins 1.5, 12, 45, and 137.5μm respectively to simulate Duguid (1946) cough droplet size distribution. Objective of the study was to examine different configurations of ventilation elements for mixing ventilation (MV) in the room which uses combined MV and Personalized Ventilation (PV) strategy. Desktop PV air terminal device (ATD) supplied 10 l/s of air at 23°C and room temperature was 26°C. Computational thermal manikin (CTM) was placed in the room to represent a PV user as well as a heat source. Different decay characteristics were exhibited by different MV configurations for the same position of the cough droplets source. When source of expiratory droplets located beneath the exhaust grill and air supplied on the further side of the CTM (Case 1) showed the best capabilities in reducing the number of airborne droplet nuclei among the studied cases.