Direct numerical simulation of a three-dimensional particle laden plane mixing layer considering inter-particle collisions

To investigate the behavior of inter-particle collision and its effects on multiphase flow, the direct numerical simulation of a three-dimensional gas–solid two-phase plane mixing layer is conducted. The flow is assumed to be temporally evolving and incompressible. The particle trajectories are traced by the one-way or two-way coupled Lagrangian method separately. The deterministic hard-sphere model is used to describe the inter-particle collision. Calculations are performed for a particle Stokes numbers of 3. The results show that the preferential concentration phenomenon of particles is found after the beginning of the rolling up of the large-scale vortex structures due to the influence of the vortex. It is also found that the inter-particle collision occurs frequently in the local regions with higher particle concentration of the flow field. The evolution of inter-particle collision can be divided into 3 stages under the influence of the growth of the vortex and the particle dispersion. The results under the two-way coupling show that the particle distribution is more uniform. The modifications of the mixed fluid thickness, the Reynolds stresses, and the mean stream-wise velocity of two phases due to inter-particle collision are quantitatively investigated.

► We used the hard-sphere model and DNS method to study the collisions.
► The collisions occur frequently in higher particle concentration regions.
► The evolution of collisions can be divided into 3 stages.
► The particle distribution is more uniform due to the collisions.
► The modifications due to the collisions are quantitatively investigated.