Modeling particle distribution and deposition in indoor environments with a new drift–flux model

A new drift–flux model for particle distribution and deposition in indoor environments is developed. Gravitational settling and deposition are examined thoroughly and the model is applied to simulate particle distribution and deposition in a ventilated model room. The turbulent airflow field is modeled with the renormalization group (RNG) k–ε turbulence model. For the particulate phase, the concentration field is divided into two regions, the core region and the concentration boundary layer. The concentration distribution in the core region is obtained by solving a three-dimensional particle transport equation. Deposition flux towards the wall is determined with a semi-empirical particle deposition model. With the feasibility of the proposed Eulerian model, the influences of the other deposition mechanisms can be captured easily into the model. The model is validated experimentally and a good agreement between numerical and experimental results is found. Inferring from the result, it shows that the well-mixed assumption cannot hold for coarse particles. The model presented in the current work provides an efficient and reliable tool for investigation of spatial and temporal particle concentration in enclosures and the result will be very useful for improving our current understanding of human exposure assessment.