RANS modelling and LES of particle deposition in a turbulent square duct flow

The ability of a RANS approach, coupled with a Lagrangian particle tracking technique, to predict particle dispersion and deposition in a high Reynolds number duct flow has been assessed for spherical particles in the range 5-500 mu m, with the results compared with LES-based predictions. The predicted time-dependent particle dispersion and deposition show good agreement with LES, with similar agreement in the spanwise direction for all but the largest particles. In the latter case, analysis of the forces acting on the particles, and mean relative slip velocities, indicates that this is due to an under-prediction of the spanwise drag force. This results in LES predicting that the largest particles tend to concentrate at the comers of the duct floor, whilst for RANS they deposit with a more even distribution.