CFD prediction of air–solid flow in 180° curved duct

Gas–solid two-phase flow in 180° curved duct is simulated using a two-way coupling Eulerian–Lagrangian approach. Reynolds averaged Navier–Stokes equations (RANS) and four turbulence models namely; standard k–ε model, RNG (Renormalization Group) based k–ε model, Low-Re k–ε model and an extended version of the standard k–ε model are adopted. The effects of particle rotation and lift forces are included in the particle tracking model. The present predictions are compared with published experimental data for single-phase and two-phase flows. The comparisons show that the RNG based k–ε model predicts the flow behaviour better than other models. Furthermore, the particles concentration and velocity are compared very well with published data. The effects of inlet gas velocity, bend geometry, loading ratio and particle size on the flow behaviour and bend pressure drop are also discussed. The results show that the flow behaviour is greatly affected by these parameters.