Behavior of a swirling flow in a spray dryer was studied numerically. Eulerian and Lagrangian approaches were used to describe the continuous and dispersed phases, respectively, and particle-source-in-cell (PSI-Cell) model was used to take account of the phase interaction. Standard k-ε turbulence model was adopted for the gas phase calculation and the wetted surface model was used to estimate the drying rates of the particles. Calculations show that the larger swirl induces another flow recirculation at the centerline portion of the spray chamber besides the one at the upper corner of the chamber ; at the recirculation zones, the temperature is lower and more humid (that is, the particles are drying slowly), but the particle residence time becomes longer and the overall performance can be improved with the larger swirl number.
