Numerical simulation of airflow and particle distributions with floor circular swirl diffuser for underfloor air distribution system in an office environment.

In the present study, an underfloor air distribution (UFAD) system with a circular swirl diffuser was simulated in an office room using a three-dimensional model when thermal sources were present in the room. An Eulerian-Lagrangian model was used to predict the characteristics of air and particle phases. In the Lagrangian particle model, the effects of drag, lift, Brownian, and thermophoresis forces were considered.