NUMERICAL STUDY OF EXPIRATORY DROPLET DISPERSION USING A NEW EULERIAN MODELING APPROACH

The increasing incidence of airborne transmitted diseases indoors has prompted the attention ofstudying expiratory droplet dispersion and transport in built environments. Droplet dispersion in aroom under the conventional well-mixed and displacement ventilation is simulated. In this work, asource (i.e. a patient) and a receptor (i.e the susceptible object) were located in a mechanicalventilated room. This study evaluated droplet dispersion and mixing under well-mixing anddisplacement ventilation scheme. Two droplet nuclei sizes, 0.01 and 10 ?m, are selected as theyrepresent very fine and coarse droplets. The flow field is modeled using k-? RNG model. A newEulerian drift-flux methodology is employed to model droplet phase. Under the conventionalventilation scheme, both fine and coarse droplets are homogeneously dispersed within approximately50 s. Droplet nuclei exhibit distinctive dispersion behavior, particularly for low airflowmicroenvironment. After 210 s of droplet emission, gravitational settling influences the dispersion for10 ?m droplets, and concentration gradient can still be observed for displacement ventilation.