Stability and accuracy of numerical investigation of droplet motion under local ventilation airflow

It is challenging to predict droplet motion in numerical studies of particulate transport in indoor environment. This paper attempts at providing answers on this topic while using a Eulerian-Lagrangian method. The effect of the droplet release number and evaporation on prediction stability and accuracy was evaluated by modeling the droplet motion for two initial droplets (10 and 100 μm) and three different airflow patterns in an upper-receiving ventilation system. The results show that the effect of the droplet release number on prediction stability depends on the spatial scale of droplet motion, airflow pattern, and droplet number in a certain domain. Evaporation affected the motion and distribution of droplets, especially for those with an initial diameter of 100 μm. The number of droplets with an initial diameter of 100 μm escaping into the indoor environment was over predicted when ignoring droplet evaporation. The results may contribute to more accurate predictions of droplet transport by numerical simulation.