Coupled CFD–DEM of particle-laden flows in a turning flow with a moving wall

• Particle–fluid interactions in the system similar to a slot coating die are modeled using the discrete element method.
• Particles move toward the walls of the channel near the bend with long residence times.
• Adhesion and drag forces lead to particle agglomeration especially in regions with high residence time.

The nature of the particle–solid interactions and particle–fluid interactions in rectangular duct bend geometry with/without a moving wall is studied, taking into account particle collision, colloidal, and hydrodynamic forces, and four way coupling between the fluid flow and particles. The focus is on systems where particles and fluid phase have similar length scales, fluid Reynolds number (Ref) ∼ 1, and particle's Stokes number (St) ∼ 1. Particles move toward the walls of the channel near the bend, and have long residence times in these regions. Buoyancy force has negligible effect on particle motion, where adhesion and drag forces lead to particle motion and agglomeration patterns. The effect of a free surface on agglomeration sites in the turning flow is elucidated.